Key facts
- Emergencies
- A change in vision or eye pain after filler: call 995 now. Stroke signs (new weakness of the face, an arm or a leg, or slurred speech): call 995 now, and do not travel to a clinic first. Pale, dusky or mottled skin, or pain that is getting worse: urgent assessment by the doctor who injected you, or at A&E, now.
- When problems appear
- In a systematic review of hyaluronic acid filler, 72.6% of adverse events were immediate and long-term events were rare (4.8%) (de Castro Costa 2025).
- Late lumps
- Delayed inflammatory reactions after hyaluronic acid ran at 1.1% a year in prospective studies (Chung 2020); in one review, granulomas after PMMA, poly-L-lactic acid, calcium hydroxylapatite or polycaprolactone appeared from 1 week to 15 years after injection (Wang 2025).
- Any filler
- Of 240 granulomas in an international ultrasound study, 50.4% followed hyaluronic acid, a share of the cases collected rather than a measure of risk (Wortsman 2025).
- After surgery
- Silicone chin granulomas came back in 44.4% after surgery alone and 5.89% when medical treatment was added (Harlim 2026); after fat nodules from fat grafting were cut out under the eyes, a dent was reported in 18.18% and 29 of 33 patients were satisfied (Li 2024).
- Scan first
- An international expert consensus calls ultrasound mandatory for managing filler complications (Velthuis 2025).
The evidence in brief, and why it says get assessed first
Patients come to Dr Sin Yong after being told that a filler lump has to be cut out. This page sets out what the medical journals report, problem by problem and product by product, so that the decision is made on evidence. In brief:
- Most problems appear straight away, and long-term ones are rare. In a systematic review of hyaluronic acid filler, 72.6% of adverse events were immediate and long-term events were rare (4.8%) (de Castro Costa 2025).
- Lumps can appear late, after any kind of filler. Delayed inflammatory reactions after hyaluronic acid ran at 1.1% a year in prospective studies (Chung 2020), and in one systematic review, granulomas after PMMA, poly-L-lactic acid, calcium hydroxylapatite or polycaprolactone appeared from 1 week to 15 years after injection (Wang 2025).
- Any filler can cause a granuloma. Of 240 granulomas in an international ultrasound study, 50.4% followed hyaluronic acid, a share of the cases collected rather than a measure of risk (Wortsman 2025).
- Surgery to remove filler has measurable harms, and in the same series most patients improved or were satisfied. Published series report thick, raised scars and nerve injury after non-absorbable filler was drained and a facelift done (Gadallah 2023), dents after fat nodules from fat grafting were cut out under the eyes (Li 2024), and silicone chin granulomas returning in 44.4% after surgery alone (5.89% when medical treatment was added) (Harlim 2026). In the same series, the facelift surgery was described as successful in all 50 women, 29 of 33 patients were satisfied after the fat nodules were removed, and the chin operation improved chin shape and redness.
- The scan comes first. An international expert consensus calls ultrasound mandatory for managing filler complications (Velthuis 2025).
Before you agree to an operation, know what it means:
- A scar. Every cut through the skin of the face heals with a scar.
- A dent. Cutting out a lump takes tissue with it, and the area can heal hollow or uneven.
- Nerve injury. Nerves that give the face feeling and movement run close to where filler sits. An injured nerve can leave numbness, or weakness in a smile, a lip or a brow.
- Product left behind. Filler spread through tissue is hard to remove completely.
- No way back. Tissue that has been cut out cannot be put back.
In Dr Sin Yong's practice, almost every hard lump is treated without surgery. If yours is one of the few that needs surgery, you are told plainly, and why. Dr Sin Yong maps each lump with ultrasound, dissolves hyaluronic acid after a skin test, and treats material that cannot be dissolved, silicone included, with the Sculpting mode of Time Freeze Laser LCLR®, without an incision. Each problem has its own page: hard lumps after filler or skin boosters, filler granuloma, filler removal surgery and filler complications.
Each table below gives a problem, what a study reports with its figure, the reference (the full list is at the end of the page), and what it means for you. A systematic review gathers earlier studies; a case series describes one group of patients, usually without a comparison group.
Hyaluronic acid filler: swelling, late lumps, filler that stays, and granulomas
Most lip, cheek, chin and under-eye filler is hyaluronic acid.
Swipe sideways to see the whole table.
| Problem | What the journals report | Reference | What this means for you |
|---|
| Swelling, bruising or tenderness straight after the injection | In a systematic review of 24 studies (1,410 patients followed for at least 12 months), most adverse events were immediate (72.6%) and long-term events were rare (4.8%). | de Castro Costa 2025 | Expected, and it eases steadily as the area settles. A lump that stays is scanned. |
| Swelling or lumps that appear later (a delayed reaction) | A systematic review put delayed inflammatory reactions at 1.1% a year in prospective studies; most retrospective studies estimated them at under 1% over 1 to 5.5 years. | Chung 2020 | Red, hot, painful, swollen or draining, or a fever: a doctor the same day; if no doctor can see you today, A&E. It is treated medically first. Not inflamed, and the lump is the hyaluronic acid itself: dissolved after a scan and a skin test. |
| Filler still there long after it was expected to go | The studies using 3D imaging found 60–86.4% of hyaluronic acid still present at 12 months and 50–86% at 24 months; ultrasound showed it for 12 to 36 months. | de Castro Costa 2025 | Earlier filler may still be there when more is added. The scan shows what remains before anything else is injected or dissolved. |
| A granuloma: the body's immune reaction walling off the filler | Of 240 granulomas after cosmetic fillers in an international ultrasound study, 50.4% followed hyaluronic acid. | Wortsman 2025 | A share of the cases collected, not a measure of risk. Hyaluronic acid can cause a true granuloma, not only a lump of product, and the hyaluronic acid in it is dissolved after a scan and a skin test; some need more than dissolving. Red, hot or painful: a doctor the same day; if no doctor can see you today, A&E. |
Two problems are well recognised after hyaluronic acid filler but are not measured by the studies on this page: filler that moves away from where it was placed, and puffiness on the upper cheek below the eye, called malar oedema, after under-eye or cheek filler. Ultrasound shows where the filler sits, how deep it is and how far it has spread, and what it is likely made of. More is in filler migration.
Hyaluronidase acts on hyaluronic acid only. The filler is mapped with ultrasound and your allergy history is checked. Before planned dissolving, Dr Sin Yong always does a skin test: a small amount of hyaluronidase is injected just under the skin to check for a reaction. A small first dose follows, with a review at about 48 hours, because dissolving more than the excess can leave a hollow. In an emergency such as a blocked blood vessel, dissolving is not delayed for a skin test. Infected hyaluronic acid is dissolved only once the infection is under control, because dissolving never replaces treating the infection. Any refilling waits at least two weeks after dissolving. More is in how hyaluronidase is used.
“Dissolving filler is not an undo button.”
Dr Sin YongOn what dissolving can and cannot do
Collagen stimulators: Sculptra, Radiesse, Ellansé and Juvelook
Collagen stimulators prompt the body to build collagen around their particles. In the studies below, lumps were the commonest problem reported.
Swipe sideways to see the whole table.
| Problem | What the journals report | Reference | What this means for you |
|---|
| Nodules after poly-L-lactic acid (Sculptra) | In 130 patients at one clinic, nodules were the commonest side effect (8.5%), mostly felt rather than seen, with the highest rates in the hands and cheeks; the authors conclude that the rate of nodule formation is low. | Palm 2010 | A small nodule that can be felt but not seen can sometimes be left alone. One that shows or bothers you is scanned. |
| Nodules after calcium hydroxylapatite (Radiesse) | A review of 21 studies (5,081 treatments in 2,779 patients) found an adverse event in about 3% of treatments, almost all of them nodules; most nodules could not be seen and settled without treatment. | Kadouch 2017 | Most settled on their own in that review. A nodule that lasts, shows or bothers you is scanned. |
| Granulomas, sometimes years later | In a systematic review of 117 patients with granulomas after collagen stimulators, reported cases followed PMMA (35%), poly-L-lactic acid (31%), calcium hydroxylapatite (27%) and polycaprolactone (4%). Across all four products, they appeared from 1 week to 15 years after injection, on average about 20 months, most often around the mouth. | Wang 2025 | A new lump long after any of these is worth a scan. Red, hot, painful, swollen or draining, or a fever: a doctor the same day; if no doctor can see you today, A&E. |
| Lumps that do not settle | In 55 complications after poly-L-lactic acid, calcium hydroxylapatite and polycaprolactone, collected by ultrasound specialists in Brazil, nodules made up 89% and usually appeared more than a month after treatment. Despite saline, hyaluronidase, diluted medical treatment and energy-based devices, only 5 resolved completely, and hyaluronidase helped only where calcium hydroxylapatite had been mixed with hyaluronic acid. | Ianhez 2024 | These lumps can persist. Hyaluronidase does not dissolve the stimulator, but the lump can still be treated without an incision. That study did not use the Sculpting mode, and its figures do not apply to it. |
Sculptra is poly-L-lactic acid, Radiesse calcium hydroxylapatite, Ellansé polycaprolactone, and Juvelook poly-D,L-lactic acid in a hyaluronic acid carrier. Hyaluronidase reaches only the hyaluronic acid: Juvelook's carrier, or the hyaluronic acid part of a hybrid product such as HArmonyCa, not the stimulator itself. For Juvelook, the published reports are single cases and small series, so no rate is given here.
Material that cannot be dissolved can still be treated without an incision. Dr Sin Yong maps each nodule with ultrasound and treats nodules and granulomas from all of these products with the Sculpting mode of Time Freeze Laser LCLR®, without an incision. More by product is in Sculptra gone wrong, Radiesse lumps, Ellansé nodules and correction and Juvelook lumps.
Non-absorbable fillers: silicone, polyacrylamide gel and PMMA
The body does not break these fillers down, so problems can appear years after the injection, as they did in the lip series below (Kastner 2018).
Swipe sideways to see the whole table.
| Problem | What the journals report | Reference | What this means for you |
|---|
| Silicone granulomas | Silicone oil accounted for 3.8% of 240 granulomas in an international ultrasound study. | Wortsman 2025 | A share of the cases collected, not a measure of risk. Silicone cannot be dissolved, but it can still be treated without an incision. |
| Silicone that spreads through the tissue | Authors who operated on 35 patients with silicone chin granulomas state that complete surgical removal of injected silicone is nearly impossible because it migrates, and that silicone residues cause a high rate of recurrence. | Harlim 2026 | An operation can leave silicone behind. Ask what would be left, and have the area scanned first. |
| Polyacrylamide gel (Aquamid) that hardens and moves | In 11 patients with the gel in their lips, it had spread through all three layers of the lip, with scar tissue in every one, and had moved into the lining and the skin around the mouth, even years after injection. | Kastner 2018 | Gel woven into tissue cannot be dissolved, but it can still be treated without an incision. |
| PMMA (Artecoll, Artefill, Bellafill) granulomas | PMMA made up 35% of reported cases in a systematic review of granulomas after collagen stimulators, and 8.3% of 240 granulomas in an international ultrasound study. | Wang 2025; Wortsman 2025 | PMMA cannot be dissolved, but it can still be treated without an incision. |
In older and overseas treatments the material is often unknown, which is one more reason the scan comes first. Dr Sin Yong maps silicone, polyacrylamide gel and PMMA with ultrasound and treats them with the Sculpting mode of Time Freeze Laser LCLR®, without an incision; none of the studies in this table tested it. A red, hot, painful, swollen or draining lump in old gel or silicone, or a fever: a doctor the same day; if no doctor can see you today, A&E. Such a lump is treated medically first. More is in silicone filler lumps and polyacrylamide filler lumps.
Skin boosters: Profhilo, polynucleotides and diluted collagen stimulators
Most skin boosters are placed in many small injections close to the surface, and bumps at the injection points are expected. A lump that stays or appears later is scanned. Published figures for Profhilo and polynucleotides are in skin booster side effects.
- Profhilo is hyaluronic acid, so a lasting lump made of it can be dissolved after a scan and a skin test.
- Polynucleotides such as Rejuran are not hyaluronic acid, so a lump from them is not dissolved by hyaluronidase, but it can still be treated without an incision.
- Diluted collagen stimulators. No study on this page measures lumps after collagen stimulators diluted as boosters; the figures for these products are in the collagen-stimulator table above. These lumps are not dissolved by hyaluronidase, but they can still be treated without an incision.
- Exosomes. As of October 2026, no injectable exosome product is approved by the Health Sciences Authority in Singapore, and Dr Sin Yong uses exosomes only on the skin surface.
A booster is still an injection. A red, hot, painful, swollen or draining lump after a booster, or a fever: a doctor the same day; if no doctor can see you today, A&E.
Surgery to remove filler: what the published series report
These figures come from case series, mostly without comparison groups, from different teams, fillers and areas of the face. They do not predict what will happen to you. They show what can happen.
Swipe sideways to see the whole table.
| Problem | What the journals report | Reference | What this means for you |
|---|
| Scars | After non-absorbable filler was drained and a facelift with fat grafting done in 50 women, 5 had thick, raised scars, 2 had wound infections and 1 had an earlobe pulled out of shape. | Gadallah 2023 | Every cut through the skin of the face heals with a scar. Ask where yours would sit. |
| Nerve injury | In the same 50 women, 4 had neuropraxia, a nerve that stops working for a time, in the branch of the facial nerve that moves the lower lip. | Gadallah 2023 | Nerves that give the face feeling and movement run close to where filler sits. Ask which ones run near your lump. |
| Dents and second operations | After fat nodules from fat grafting were removed from the tear trough through the inside of the eyelid in 33 patients, a localised dent was reported in 18.18%, and 3 of 66 eyelids needed a second procedure. | Li 2024 | Cutting out a lump takes tissue with it, and the area can heal hollow or uneven. |
| Silicone left behind, and lumps that come back | After silicone chin granulomas were cut out in 35 patients, they returned in 44.4% of those who had surgery alone and 5.89% of those who also had medical treatment, and chin shape worsened again in the surgery-only group. | Harlim 2026 | Filler spread through tissue is hard to remove completely. In this series, granulomas came back much less often when medical treatment was added after the operation. |
| Gel that cannot all be taken out | In 11 patients with polyacrylamide gel in the lips, the gel could not be drawn out with a needle; taking it out meant reconstructing the lip, gel left in the lip lining had to be accepted, and 1 had severe necrosis, death of tissue, in the upper lip. | Kastner 2018 | Tissue that has been cut out cannot be put back, and an operation cannot be undone. |
Where surgery did well
- The silicone chin operation improved chin shape and redness, with a complication rate of 2.86% (Harlim 2026).
- After lip reconstruction for polyacrylamide gel, 10 of 11 results were aesthetically satisfying (Kastner 2018).
- After fat nodules were removed from the tear trough, 29 of 33 patients were satisfied (Li 2024).
- The authors of the facelift series describe the surgery as successful in all 50 women (Gadallah 2023).
- In the systematic review of granulomas after collagen stimulators, surgical removal often resolved symptoms (Wang 2025).
- In 173 patients with granulomas after fillers, including illegal materials, satisfaction was higher after the granuloma was cut out than after injection treatment (a median of 4 against 3 on a five-point scale), in a comparison that was not randomised (Park 2012).
Surgery has a place. The point is the order: scan first, decide after. Some lumps do need a procedure: an abscess may need draining, and a lump that does not look like filler on the scan may need a tissue sample. Being scanned and assessed first does not rule out an operation later, and an operation cannot be undone. More is in filler removal surgery.
Ultrasound: what the scan shows, and what it cannot prove
Ultrasound shows where the filler sits, how deep it is and how far it has spread, and what it is likely made of. This is what the studies report about it:
Swipe sideways to see the whole table.
| Question | What the journals report | Reference | What this means for you |
|---|
| Does the scan match what a biopsy shows? | In 231 people with firm lumps after filler, ultrasound agreed with the tissue diagnosis in 85.7% of the 70 who had a biopsy. | Wang 2026 | The scan shows what a lump is likely made of; it does not prove it. Where it does not look like filler, further tests, including a tissue sample, are arranged. |
| What do firm lumps turn out to be? | The lumps fell into seven ultrasound types; the commonest were collections of filler that was not hyaluronic acid (37.2%) and granulomas around such filler (22.5%). | Wang 2026 | In that study, most firm lumps were not hyaluronic acid, so dissolving alone would not have reached them. |
| Does the type of lump change the treatment? | Granulomas around remaining filler that was not hyaluronic acid did better with non-invasive treatment; granulomas with no filler left, and hyaluronic acid with a granuloma, did better with invasive treatment; invasive treatment gave greater improvement overall. | Wang 2026 | What the lump is on the scan, not just how hard it feels, decides the order of treatment, surgery included. That study did not use the Sculpting mode, and its figures do not apply to it. |
| What do experts recommend? | An international panel of 15 experts from seven specialties in 11 countries agreed that ultrasound is mandatory for managing filler complications, that fillers already in place should be identified before more is injected, and that injections into a lump to treat a complication need ultrasound guidance to be placed precisely. | Velthuis 2025 | Ask whether your lump has been scanned before any decision, surgery included. |
| Where do granulomas sit? | In 240 granulomas, ultrasound showed dark nodules or dark tissue around filler deposits, most often in the fat beneath the skin (37.1%) and in the lower eyelid, under-eye and inner cheek area (41.7%). | Wortsman 2025 | The scan shows how deep a granuloma sits and how far it reaches. |
Dr Sin Yong performs the scan himself, and the plan follows what it shows. A lump that keeps growing, sits where nothing was injected or feels fixed to deeper tissue is assessed for other causes before anything is treated as filler. More on scanning is in ultrasound-guided filler correction.
What the journals cannot tell you
The figures on this page come from published studies, and they have real limits:
- Most of the evidence is case series and reviews. Serious complications are rare, so trials are too small to measure them well, and most of what is known comes from case series, which usually describe one group of patients without a comparison group, and from reviews that gather them.
- Rates differ widely. How a study is done changes the number: delayed reactions after hyaluronic acid ran at 1.1% a year in prospective studies but under 1% over 1 to 5.5 years in most retrospective ones (Chung 2020). The product, the area, the amount and the technique also differ from study to study.
- A share is not a risk. When a study says half of its granulomas followed hyaluronic acid, it describes the cases it collected, not the risk with one product.
- No randomised trial has compared surgery with treatment without an incision. The comparisons that exist are not randomised, such as surgery alone against surgery plus medical treatment for silicone in the chin (Harlim 2026), and cutting granulomas out against injection treatment (Park 2012). The other surgical figures come from series in which each team reports its own patients, with different fillers and areas: gel in the lips, fat under the eyes, non-absorbable filler drained before a facelift.
- No published paper has studied the Sculpting mode of Time Freeze Laser LCLR®. Most published laser studies on filler lumps place a fibre inside the lump, which is a different technique, and their figures do not apply to it. What Dr Sin Yong reports from his own practice is clinical experience, not a published study.
- Figures describe groups, not you. They show what can happen. They cannot predict what will happen to one person.
What expert consensus does support is the order: an international panel calls ultrasound mandatory for managing filler complications (Velthuis 2025). Scan first, decide after.
Emergencies after filler: the signs that cannot wait
Emergencies after filler are rare, but the harm can last. A review of the world literature found 48 new published cases of partial or complete vision loss after filler between January 2015 and September 2018. The commonest sites were the nose (56.3%), between the brows (27.1%), the forehead (18.8%) and the smile lines (14.6%), and 81.3% involved hyaluronic acid. Skin changes were seen in 43.8%, and central nervous system complications, in the brain or spinal cord, in 18.8%. Ten (20.8%) recovered their vision fully and 8 (16.7%) partly, and no single treatment was consistently effective (Beleznay 2019).
Urgent: a change in vision or eye pain after filler: call 995 now. Skin that turns pale, dusky or mottled, or pain that is getting worse, needs urgent assessment by the doctor who injected you, or at A&E, now. See the warning signs of a blocked blood vessel after filler.
- Stroke signs (new weakness of the face, an arm or a leg, or slurred speech): call 995 now, and do not travel to a clinic first.
- Spreading redness with a fever, feeling faint, confused or very unwell, or swelling around the eye with pain: call 995 or go to A&E now.
- A red, hot, painful, swollen or draining lump, or a fever: a doctor the same day; if no doctor can see you today, A&E. More is in infection after filler.
- Difficulty breathing, a tight throat, swelling of the tongue or throat, or swelling that spreads quickly across the face, after any injection, including hyaluronidase, can be a serious allergic reaction: call 995 now. Itch, hives or swelling that spreads beyond the treated area: contact the clinic that injected you the same day.
Skin that is dying after a blocked blood vessel (necrosis) is an emergency. It needs urgent, more intensive care than a lump does, starting now. A blocked blood vessel is never treated with the Sculpting mode of Time Freeze Laser LCLR® or any other laser. Do not use WhatsApp, or wait for a scan or a booked appointment, for any of these signs. More is in filler necrosis.
Tried other treatments and almost given up?
Many patients who come to see Dr Sin Yong about filler complications tell him they have tried almost everything else and had given up hope. Having tried other treatments does not mean nothing more can be done: what is done next depends on what the scan shows.
That history is useful. Knowing what was injected, when, and what has already been tried often explains why a problem has stayed: hyaluronidase acts only on hyaluronic acid and only where it reaches, some fillers are not hyaluronic acid at all, and swelling or fluid can look like filler. Ultrasound shows which of these applies, and the plan starts from there. For material that cannot be dissolved, Dr Sin Yong uses the Sculpting mode of Time Freeze Laser LCLR® for nodules large and small, without an incision. How each person responds varies.
If you have been told nothing more can be done, it is still worth having the area scanned: ultrasound shows what is there, and the plan is made from that. Bring any records of past treatments, product names and dates if you have them. More on this is in when filler dissolving has not worked.
How Dr Sin Yong uses this evidence
The evidence above is why Dr Sin Yong scans before anything is decided. For each lump he:
- Maps. He scans it himself with ultrasound: where the filler sits, how deep it is, how far it has spread, what it is likely made of and the vessels nearby.
- Treats inflammation or infection first. A red, hot, painful, swollen or draining lump, or a fever: a doctor the same day; if no doctor can see you today, A&E. Dr Sin Yong sees these lumps the same day and treats them medically before anything else.
- Dissolves hyaluronic acid, if the lump is the hyaluronic acid itself. Your allergy history is checked, and a skin test comes first; a small first dose follows, with a review at about 48 hours.
- Treats what cannot be dissolved, without an incision. He treats silicone, polyacrylamide gel, PMMA, Ellansé, Sculptra, Juvelook, Radiesse, granulomas, layered products and excess fat graft with the Sculpting mode of Time Freeze Laser LCLR®, his own protocol on a long-pulsed 755 nm and 1064 nm laser platform, directed at the mapped lump, without an incision. Like any laser, it can cause blistering or a change in skin colour, so settings are chosen for your skin. This step rests on his clinical experience: no published study has tested the Sculpting mode.
- Reviews. Each lump is reassessed, and any further visit is planned from what is seen.
He does not inject more filler to hide a lump. He explains the risks and limits of each option at the assessment, including waiting where that is reasonable and surgery where it is needed. Dr Sin Yong developed the Time Freeze Laser LCLR® protocol himself and performs every scan and treatment himself on Orchard Road. He has been invited to share his clinical expertise in Seoul, Dubai, Bangkok and São Paulo, including as a Global Key Opinion Leader. More on the laser is in the Sculpting mode of Time Freeze Laser LCLR®.
