Skin booster side effects:
what is normal, what is not, and what to do

What is normal straight after a skin booster, and what is not

Most skin boosters are placed as many small injections into the skin; Profhilo is placed at a small number of points on each side. Either way, the skin reacts straight away. Small raised bumps at the injection points, swelling, redness, bruising and tenderness are expected. They are temporary, and they ease steadily as the skin settles. How long that takes varies with the product, the area and your skin.

These reactions are common, and on their own they are not a sign that anything has gone wrong. In a study of polynucleotide injections into the lips of 30 people, every one had swelling 30 minutes afterwards, 90% had pain and 77% redness, and the reactions were mostly mild and transient (Rho 2025). In a 16-week study of 64 women treated with the hybrid hyaluronic acid in Profhilo, minor, temporary reactions at the injection points occurred in 23% (Sparavigna 2016). Polynucleotides such as Rejuran tend to leave more visible bumps at first than hyaluronic acid boosters.

What is not normal is a reaction that lasts, builds or changes character. This is how to tell them apart:

Swipe sideways to see the whole table.

Bumps that have not settled and lumps that appear later are covered in detail in lumps after skin boosters.

When a reaction after a skin booster needs a doctor today

Most reactions after a skin booster are the expected ones above. These are not, and they are not for waiting out:

• A red, hot, painful, swollen or draining lump: possible infection. Have it seen the same day. It is treated medically first, before any device and before any talk of surgery.
• Fever, or feeling unwell, with a red or swollen area: review the same day, not a planned appointment.
• Redness that is spreading, with a fever, or swelling around the eye with pain: call 995 or go to A&E now.
• Skin that darkens, turns purple or breaks down after an injected exosome product: possible skin necrosis; get urgent assessment the same day by the doctor who injected you, or at A&E.
• 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.

Until you are seen, do not squeeze, massage or try to drain a red or painful lump yourself, and do not have more product injected into the area.

Any injection into the face can rarely block a blood vessel, a skin booster included. The warning signs are the same as after filler:

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.

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.

“Dissolving filler is not an undo button.”

Dr Sin YongOn what dissolving can and cannot do

Are skin boosters dangerous? What the published figures show

The side effects in the published figures are mostly mild and temporary. A skin booster is still an injection, though, and the rarer problems are real. What is in the syringe decides what can go wrong and what can be done about it.

Hybrid hyaluronic acid

In the first three years of Profhilo use, covering more than 40,000 patients, 12 adverse-event reports were received, none serious. Most were early swelling, redness or bruising; a few were later local reactions such as swelling and lumps, attributed to hypersensitivity or injection technique, and all resolved (Cassuto 2020). Across an estimated 1.09 million facial Profhilo patients from 2018 to 2023, 371 adverse events were recorded (0.034%), most often swelling, redness and discomfort linked to the injection itself (Salti 2025).

Those are post-marketing figures, which count the problems that are reported. A study that examines every participant records the expected reactions far more often: in the 16-week study of 64 women, minor, temporary reactions at the injection points occurred in 23% (Sparavigna 2016). Minor reactions are common. Reported problems are rare. How it is placed, and what to expect afterwards, is described in hybrid hyaluronic acid bio-remodelling.

Polynucleotides

A systematic review of polynucleotides in aesthetic medicine found 9 studies, with 219 patients, of low and moderate quality; side effects were generally mild and transient, and the authors call for more rigorous studies (Lampridou 2024). Rejuran is purified from salmon DNA, so a fish allergy is asked about before treatment. More on the treatment itself is in polynucleotide injections.

Other hyaluronic acid boosters

Skinvive and other microdroplet hyaluronic acid boosters are lightly stabilised hyaluronic acid placed as many small injections into the skin. The expected reactions are the same, and because they are hyaluronic acid, a lasting lump made of the booster can be dissolved.

The rarer, more serious problems

The problems covered below are infection, including unusual bacteria after mesotherapy; collagen stimulators diluted and used as boosters, whose lumps do not dissolve; and exosome products injected although they are made for use on the skin surface. Any injection can also rarely block a blood vessel. Material that cannot be dissolved can still be treated without an incision. More on the products themselves is in skin boosters in Singapore.

Not normal: delayed nodules and granulomas

When a hyaluronic acid booster such as Profhilo goes wrong, it shows as a bump that has not flattened, a lump or swelling that appears later, an infection or, rarely, a blocked blood vessel. Later local reactions such as swelling and lumps were among the reports in the first three years of Profhilo use, and all resolved (Cassuto 2020).

A review of nodules after soft-tissue fillers, rather than boosters, describes two kinds. Non-inflamed lumps usually appear soon after the injection and come from where the product was placed. Inflammatory nodules can appear days to years afterwards; they are commoner with non-absorbable fillers such as silicone but also follow temporary fillers such as hyaluronic acid and collagen, and infection or a biofilm, bacteria living on the product, can be the cause (Ledon 2013).

Granulomas

A granuloma is a firm lump that forms when the body walls off material it treats as foreign. In a published case, a woman developed multiple foreign-body granulomas across the face after mesotherapy with unauthorised products; colour Doppler ultrasound was used for the diagnosis, and medical treatment was successful (Zhang 2023). Collagen stimulators diluted and used as boosters can also form nodules, as set out below. More on granulomas is in filler granulomas.

What can be done depends on what the lump is made of. Hyaluronidase dissolves hyaluronic acid only, so a lump from a hyaluronic acid booster can be dissolved, while polynucleotides, collagen stimulators and anything else that is not hyaluronic acid are not dissolved by hyaluronidase. Those can still be treated without an incision. A scan comes first.

Infection, including mycobacteria after mesotherapy cocktails

Mesotherapy describes a technique: many small, superficial injections of a solution into the skin. Some skin boosters are given this way, and so are cocktails of vitamins and other ingredients. Any injection can carry bacteria into the skin, and an infection shows as redness, heat, pain and swelling that build rather than ease, sometimes with pus or a fever.

A rare but serious cause after skin injections is a group of bacteria called rapidly growing mycobacteria, related to the one that causes tuberculosis. In 16 patients treated by one practitioner, painful, red, draining lumps appeared at mesotherapy injection sites, mostly from Mycobacterium chelonae. All needed surgical drainage, antibiotics were given for an average of 14 weeks, and healing took an average of 6.2 months (Regnier 2009).

The practical points:

• A red, hot, tender, swollen or draining lump is treated medically first, before any device and before any talk of surgery.
• Fever, or feeling unwell with a swollen lump, needs review the same day; redness that is spreading, with a fever, means calling 995 or going to A&E now.
• A lump that keeps draining, or does not settle with the usual treatment, needs a sample of pus or tissue sent to the laboratory with a request to look for mycobacteria, because they are treated differently.
• No laser or other device is used on an active infection.

More is in infection after filler and other injections.

Diluted collagen stimulators used as boosters: lumps that cannot be dissolved

Some treatments offered as skin boosters are collagen stimulators, diluted and injected into the skin: calcium hydroxylapatite (the material in Radiesse), poly-L-lactic acid (Sculptra) or poly-D,L-lactic acid (Juvelook and similar products). They are particles that prompt the body to lay down collagen, not hyaluronic acid, and that changes what happens if a lump forms.

• Diluted calcium hydroxylapatite. A global consensus on diluted and hyperdiluted calcium hydroxylapatite, used off-label for loose skin and fine wrinkles, lists bruising, mild pain, swelling and firmness as injection-related effects, and reports more problems when less-diluted product is placed too superficially in thinner, darker skin (Goldie 2018).
• Poly-D,L-lactic acid microspheres. Brazilian experts who set out how to reconstitute, place and dose these microspheres (Aesthefill) in aesthetic use generally, not only as boosters, name nodules and granulomas as the problems to keep to a minimum, and note that clinical trials remain limited (Magacho-Vieira 2024).
• Collagen stimulators in general. In 55 complications from poly-L-lactic acid, calcium hydroxylapatite and polycaprolactone (Ellansé) reported by Brazilian ultrasound experts, a series of collagen stimulators in general rather than boosters specifically, nodules made up 89% and usually appeared more than a month after treatment. Despite saline, hyaluronidase, medical treatment injected into the lumps and energy-based devices, only 5 resolved completely, and hyaluronidase helped only where calcium hydroxylapatite had been mixed with hyaluronic acid (Ianhez 2024). That series did not include the Sculpting mode, and its figures do not apply to it.

Why these lumps cannot be dissolved

Hyaluronidase acts on hyaluronic acid only. Calcium hydroxylapatite, poly-L-lactic acid, poly-D,L-lactic acid and polycaprolactone are not hyaluronic acid, so a lump made of them does not dissolve; in Juvelook, only the hyaluronic acid carrier does. Material that cannot be dissolved can still be treated without an incision. Dr Sin Yong maps the lump with ultrasound and treats it with the Sculpting mode of Time Freeze Laser LCLR®, without an incision. More is in Juvelook lumps and Sculptra lumps.

Exosome injections: skin necrosis in published reports

Exosomes are tiny particles that cells release as messengers. Most exosome products are made for use on the skin surface, and injecting them is not approved (Tawanwongsri 2024). Two published case reports describe what happened when they were injected:

• A middle-aged man injected with an exosome product for enlarged pores developed painful dark-red bumps, and by the third day painful purplish bumps and nodules with small crusted sores. The same product injected into his upper arm caused similar lesions. A skin sample showed dying skin cells and inflammation of small blood vessels. He improved with a week of medical treatment by mouth, with some darkening of the skin left behind. The authors note earlier reports of foreign-body granulomas at injection sites, and advise against unapproved exosome injections (Tawanwongsri 2024).
• A 38-year-old man had painful, ulcerated bumps and dusky skin on both cheeks three days after multiple exosome injections for acne scars, consistent with skin dying from a loss of blood supply. The crusts came away at two weeks without infection, leaving marked sunken scars and darkened skin, and three laser sessions gave only modest improvement. The authors call it a serious, under-reported complication of unapproved exosome injections (AlBargawi 2025).

In Singapore, no injectable exosome product is approved by the Health Sciences Authority. Exosomes are used on the skin surface, applied straight after laser or microneedling has opened fine channels in the skin. That is how Dr Sin Yong uses them; he does not inject them. Anything offered as an exosome injection deserves a plain question: what exactly is in the syringe, and under what registration?

If you have had exosomes injected and the skin is darkening, turning purple or breaking down, it can be skin necrosis: get urgent assessment the same day by the doctor who injected you, or at A&E. More on how exosomes are used is in exosome treatment in Singapore.

Anything that lasts: ultrasound first

A lump, swelling or hardness that lasts after a booster can be product, swelling, fluid, scar tissue, a granuloma, an infection or something unrelated to the booster, and from the outside they can feel the same. Ultrasound shows where the product sits, how deep it is and how far it has spread, and what it is likely made of. It also shows whether filler from earlier treatments sits in the same area, and whether there is fluid or inflammation around it.

In 15 women with lumps they could feel after hyaluronic acid filler, rather than boosters, high-frequency ultrasound showed filler deposits in 9, granulomas in 3, scar tissue (fibrosis) in 2 and a deposit with inflammation in 1, each with a typical appearance (Mlosek 2021). A 2026 review of ultrasound in cosmetic fillers describes patterns that differ by material, with hyaluronic acid appearing dark on the scan and poly-L-lactic acid bright at first and fading over time, and calls high-frequency ultrasound with colour Doppler the first-line tool for identifying the type of filler, where it sits and its complications (Khorasanizadeh 2026).

The scan shows what a lump is likely made of; it does not prove it, and where it does not look like product, further tests are arranged. Dr Sin Yong performs the scan himself, and what it shows decides what is done. More on scanning is in ultrasound-guided filler correction.

What is done for a booster problem that lasts

Red, hot, tender or draining: medical treatment first

An inflamed or infected lump is treated medically first, before any device and before any talk of surgery, with drainage of any pus and a sample sent to the laboratory. Hyaluronic acid that remains is dissolved only once the infection is under control, because dissolving never replaces treating the infection, and no laser or other device is used on an active infection.

Hyaluronic acid booster lumps: dissolved after a skin test

A lump from Profhilo, Skinvive or another hyaluronic acid booster is dissolved with hyaluronidase, which acts on hyaluronic acid only. You are asked about allergies, including bee or wasp stings and any earlier hyaluronidase. 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. He then places a small first dose into the lump he has mapped and reviews it at about 48 hours, because dissolving more than the excess can leave a hollow. In an emergency such as a blocked blood vessel, treatment is not delayed for a skin test. He waits at least two weeks after hyaluronidase before any further booster or filler in the area. More is in hyaluronidase and hyaluronidase allergy and the skin test.

What cannot be dissolved: the Sculpting mode

Polynucleotides, diluted collagen stimulators, the poly-D,L-lactic acid in Juvelook, and silicone or other non-absorbable fillers sitting under a booster are not dissolved by hyaluronidase. Many polynucleotide bumps settle on their own; one that stays is scanned before anything is decided. Material that cannot be dissolved can still be treated without an incision: Dr Sin Yong treats it 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. Like any laser, it can cause blistering or a change in skin colour, so settings are chosen for your skin. Where hyaluronic acid sits with other material, dissolving and the Sculpting mode are planned in order. See the Sculpting mode of Time Freeze Laser LCLR®.

A small lump that cannot be seen

It can sometimes be left alone and reviewed; the scan decides.

A lump that lasts after a skin booster, and only offered surgery? Get assessed first

Some patients with a lump after a skin booster are told that it has to be cut out. Before you agree to that, 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. Hyaluronic acid is dissolved after a skin test, inflammation and infection are treated medically, and material that cannot be dissolved is treated with the Sculpting mode of Time Freeze Laser LCLR®, without an incision.

Surgery has a place. Some infections need surgical drainage: every patient in the mesotherapy series did (Regnier 2009). Draining pus is a different procedure from cutting a lump out. A lump that does not look like product on the scan may need a tissue sample. The point is the order: scan first, decide after. An operation can still be done later if it is ever needed, but it cannot be undone. If you have already been offered one, Dr Sin Yong can scan the lump and give you a second opinion before you decide. What removal surgery involves is set out in filler removal surgery.

Tried other treatments and almost given up?

Many patients who come to see Dr Sin Yong about side effects and lumps after skin boosters 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 helps show 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 helps show 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 approaches skin booster side effects

Dr Sin Yong takes the history himself, including what was injected, where, when and how, performs the ultrasound scan, and carries out any dissolving and every Sculpting mode treatment on Orchard Road. He developed the Time Freeze Laser LCLR® protocol himself and has been invited to share his clinical expertise in Seoul, Dubai, Bangkok and São Paulo, including as a Global Key Opinion Leader.

He does not inject more product over a lump, and skin quality treatments are considered again only after a lump has been dealt with. He uses exosomes only on the skin surface, after laser or microneedling, and does not inject them. You do not need to have been treated here. Bring any records of product names, dates and areas, or a photo of the packaging; having none is fine. Choosing a booster in the first place is covered in which skin booster suits me.