Medically reviewed by Dr Sin Yong · Last reviewed · 11 min read
Published 7 October 2026 · Reviewed by Dr Sin Yong
Dermal filler questions fall into a few groups: what hyaluronic acid and biostimulators are, where filler helps and where it does not, migration and dissolving, and the vascular risks every injector must plan for. These 30 answers are brief and distinction-led; each links to the fuller page.

Two broad groups. Hyaluronic acid fillers occupy space, hold water and can be dissolved with hyaluronidase. Biostimulators (Radiesse, Ellansé, Sculptra) prompt your own collagen and cannot be dissolved.
Read the full page →Hyaluronic acid filler can, with hyaluronidase. Calcium hydroxylapatite, polycaprolactone and poly-L-lactic acid cannot be dissolved by enzyme and are resorbed over time. Ultrasound guidance directs the enzyme at the misplaced product rather than the whole area.
Read the full page →Only hyaluronic acid filler can be broken down with hyaluronidase. Firmer, more cross-linked gels respond more slowly, so dissolving is often staged with a review in between.
Read the full page →The rounded, heavy look from too much filler, usually layered over product still present until the total exceeds what the facial skeleton supports. It is corrected by dissolving the excess under ultrasound guidance and reassessing the face from the beginning.
Read the full page →It can. Published reviews describe filler found outside the plane where it was placed, weeks to years after injection, more often in mobile areas such as the lips. Not inevitable, but a recognised finding rather than a myth.
Read the full page →Filler entering or compressing an artery and blocking blood flow. The signs are skin that blanches or turns dusky or mottled, pain out of proportion and, rarely, any change in vision. It is an emergency treated with high-dose hyaluronidase.
Read the full page →Here, usually calcium hydroxylapatite or polycaprolactone for the support they give the bridge, with hyaluronic acid where a dissolvable option is preferred. The nose carries a higher vascular risk, which shapes technique and quantity.
Read the full page →No. Filler follows anatomy rather than age: a retruded chin or low nasal bridge can be addressed in younger adults, while fat-pad and bone volume loss appears later. The useful question is whether volume is genuinely missing.
Read the full page →Both stimulate collagen. Sculptra is poly-L-lactic acid microparticles whose effect builds gradually; Ellansé is polycaprolactone microspheres in a gel, giving volume on the day and stimulating collagen as the gel is absorbed.
Read the full page →Usually not. Filler accumulated over years has become part of how the face is supported, and removing it in one sitting can uncover laxity and hollowing. Correction is staged by region and reassessed between stages.
Read the full page →No. A filler occupies space to restore volume or projection; it does not lift tissue, tighten loose skin or act on muscle. Given to a face whose main change is descent, it produces a heavier lower face with the same sag, so laxity is assessed for lifting instead.
Read the full page →A blunt cannula pushes vessels aside rather than piercing them, which is why it is often chosen for the tear trough and temples. A fine needle is used where the anatomy calls for deep placement on bone, with aspiration and slow injection. The choice is made area by area; neither removes risk.
Read the full page →To show where existing product sits and at what depth. Ultrasound separates filler from swelling, fluid and your own tissue before anything is decided, so any dissolving is directed at the misplaced product rather than guessed at. It also shows calcium hydroxylapatite clearly.
Read the full page →The nose, the glabella between the brows, the forehead and the tear trough, because arteries there connect with the circulation of the eye. No area is free of risk, which is why product is placed in the planned layer in small amounts at low pressure.
Read the full page →A bruise is blue or purple where the needle went in, tender but not disproportionately painful, and the skin over it refills when pressed. An occlusion blanches white or mottles along an artery's territory, hurts more than it should and worsens over hours instead of settling.
Read the full page →Contact the clinic that injected you immediately; if you cannot reach them, consult another doctor or go to A&E. Do not wait for it to settle. Any change in vision means the nearest hospital emergency department or 995. Tell the doctor what was injected, where and when.
Read the full page →Very rarely, yes, when filler travels into an artery connected to the eye, most often with injections around the nose, glabella and forehead. Blurring, loss of vision, double vision or eye pain after filler is an emergency: go straight to a hospital emergency department.
Read the full page →Yes, rarely. Hyaluronidase is a medicine with its own considerations: a known allergy to it or significant reactions to bee or wasp stings are asked about beforehand, and patients are observed after injection. It also acts on the hyaluronic acid naturally present in tissue.
Read the full page →Declare blood-thinning medicines and, if medically appropriate, avoid alcohol and supplements that increase bruising, such as fish oil or vitamin E, in the days beforehand. Afterwards, avoid strenuous exercise, heat such as saunas and alcohol for about a day, and do not press on the area.
Read the full page →Filler is deferred in pregnancy and breastfeeding because its safety in these groups has not been established and the treatment is elective. It is also deferred with an active infection or cold sore near the site. A consultation to plan the order of treatment afterwards is still acceptable.
Read the full page →Hyaluronic acid draws water into itself. Placed near cheek mounds that already drain poorly, it can deepen swelling that is then hard to reverse. Filler helps a hollow along the bony rim; it does not help fluid, a fat bag or thin crepey skin, which is why the cause is examined first.
Read the full page →Yes. A true eye bag is a bulge of orbital fat, and filler is for hollows. Placing volume beside the bulge tends to blend bag and groove into one larger mound, so the lower lid looks heavier. A large bag is referred to a plastic surgery or oculoplastic specialist instead.
Read the full page →A bluish tint where hyaluronic acid gel sits too close to the surface under thin skin, which scatters light. It is commonest under the eyes, where the skin is among the thinnest on the body. Because the product is hyaluronic acid, it can be assessed and dissolved if needed.
Read the full page →A lump in the first weeks is usually product or swelling. A firm nodule appearing months or years later can be an inflammatory reaction such as a biofilm or granuloma, which needs examination rather than massage. A lump that is red, warm, tender or growing should be assessed promptly.
Read the full page →Puffiness after filler is not one problem but four: filler placed too superficially, filler that has drifted, fluid the filler is holding, or simply more volume than the face needed. Each looks different on ultrasound and each is handled differently, which is why they are separated first.
Read the full page →It cannot be dissolved, because hyaluronidase has no effect on calcium hydroxylapatite or polycaprolactone. The first step is ultrasound to establish what the lump is, how deep it sits and how long ago the product was placed. Options then range from monitoring to targeted injections.
Read the full page →A filler occupies space to restore volume, projection or contour. A skin booster acts within the skin on hydration and quality and does not project or contour. Botulinum toxin, the third injectable, relaxes muscle. Which fits depends on which tissue is responsible for the change you notice.
Read the full page →Yes. Layering new product over earlier non-resorbable filler raises the risk of nodules, so it must be declared. Where the history is unclear, previous filler of any type is scanned with ultrasound before anything is added, and removal of older non-degradable material is a more involved discussion.
Read the full page →Often, yes. Swelling settles at different rates on the two sides, and lips and tear troughs swell more than bony areas, so temporary asymmetry in the first days is common. It is not a reason to add more product; the result is judged at review once swelling has settled.
Read the full page →Under the eyes, where it reads as puffiness; in the lips, as a soft shelf above the lip border or lumps away from the injection point; and around the nose and chin. Each deposit is located first, with ultrasound where useful, and then treated deliberately.
Read the full page →Answers are brief by design and condensed from the linked pages, where the reasoning, caveats and references sit. They are general information and not a substitute for an examination; a consultation with Dr Sin Yong decides what, if anything, is advised. If something feels wrong after a treatment, read the warning signs and contact the clinic.
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