In short. Bruising, droop and other injection risks after facial treatment fall into two distinct shapes rather than one ranking of severity. The muscle-relaxing injectable mainly causes unintended weakness, bruising and heaviness that resolve over months, while a dissolvable gel filler causes lumps, delayed nodules and, rarely, a vascular occlusion needing same-day emergency care.

Key points

  • Muscle-relaxing injectable risks are about unintended movement and fade over months.
  • Filler risks are about what stays in tissue: lumps, nodules and rare occlusion.
  • Droop is waited out and sometimes partly compensated; there is no reversal agent.
  • Vascular occlusion is a same-day emergency; a dissolvable filler can be partly broken down.
  • Previous treatment and baseline asymmetry raise risk, so a pre-treatment record matters.

Two risk shapes, not one severity scale

The risks of the two substances are different in kind, and comparing them is more useful than ranking them. One set is about movement and resolves with the treatment. The other is about what is left in the tissue and can require urgent care. That difference, rather than a single scale of severity, is what decides how each complication is handled.

The risks of relaxing a muscle

The characteristic risk is that the effect reaches a muscle it was not intended for. Weakness of a neighbouring muscle produces a brow that sits lower, an eyelid that droops, or an asymmetry between the two sides. These are recognised consequences rather than accidents. They are more likely where the anatomy is unusual or the placement is imprecise, and they resolve as the effect fades over months. Bruising, a mild headache and a heavy feeling in the treated area are common and minor.

The risks of adding volume

Bruising and swelling are usual and can be marked. Lumps and irregularity can appear immediately or become visible later as the material settles, and material placed in the wrong plane or the wrong area can produce a contour that does not look natural. Delayed reactions and nodules are recognised, sometimes appearing well after treatment. The rare and serious risk is vascular occlusion, where material obstructs a blood vessel and the tissue it supplies is at risk. This is a medical emergency, and the ability to recognise it and act on it is part of what a patient is paying for.

Why are the two managed at different speeds?

A droop is managed by waiting and, where possible, by adjusting the opposing muscles. There is no reversal agent for muscle relaxation. A vascular event is managed immediately, and a dissolvable gel filler can be partly broken down with an enzyme, which is one reason the material chosen can matter when a complication occurs. The two situations call for different responses, at different speeds.

Which findings need same-day or emergency care?

These findings are grouped by how quickly they need a response.

What you notice After which injection Urgency What to do
Bruising, mild headache or a heavy feeling Muscle-relaxing injectable Minor and expected Common and minor; no urgent action
Lower brow, drooping eyelid or asymmetry Muscle-relaxing injectable Not an emergency Review the movement and wait; it fades over months
Bruising and swelling, sometimes marked Dissolvable gel filler Expected No urgent action; monitor
Lumps, irregularity or a delayed nodule Dissolvable gel filler Non-urgent review Assess; may appear immediately or well after treatment
Sudden severe pain, or skin white, dusky or mottled Dissolvable gel filler Emergency, same day Urgent assessment the same day
Vision changes after any facial injection Any facial injection Medical emergency Emergency care immediately
Fever, spreading redness or worsening painful swelling Either Prompt assessment Seek help rather than wait for it to settle

Sudden severe pain after filler, or skin that turns white, dusky or mottled, needs urgent assessment the same day. Vision changes after an injection anywhere on the face are a medical emergency. Fever, spreading redness or a painful swelling that is worsening rather than settling should prompt help rather than waiting.

What both risks have in common

Both require a face that has been examined, an injector who knows the anatomy of the area, and an arrangement for what happens afterwards. Both carry more risk in a face that has had previous treatment, where scar tissue has changed the planes and where the record of what was placed may be incomplete. Both are also carried out on faces that are asymmetric to begin with, which is why a pre-treatment record matters.

What should be settled before treatment?

Ask before treatment who to contact if something goes wrong, how quickly they can see you, and what they would do. A clinic that cannot answer that question is not organised for the risk it is taking.

Sources

Internal links

Frequently asked questions

Which of the two has the more serious risks?

They carry different risks rather than different amounts, so the honest answer is that the comparison does not resolve into one being safer. The risks of the muscle-relaxing injectable are mostly about unintended muscle weakness that fades with the treatment. Filler carries the risk of lumps and, rarely, a vascular occlusion that threatens tissue and is a medical emergency. Both need an injector who can recognise and manage complications.

What should happen if something goes wrong after an injection?

You should be able to reach the treating clinician directly, and they should be able to see you the same day. For filler, sudden severe pain, blanching of the skin, or a patch that turns dusky or mottled needs urgent assessment rather than a review appointment next week. For the muscle-relaxing injectable, a droop or asymmetry is not an emergency, and it is managed by reviewing the movement and waiting.

Can a droop be treated if it happens?

Sometimes it can be partly compensated, and often it is waited out. Because the effect fades over months, the droop resolves as the treatment does. An injector may be able to adjust the opposing muscles to reduce the asymmetry, and that is a judgement made at a review rather than immediately. There is no equivalent of an antidote.

Risks & Limitations

  • Bruising and swelling after either treatment; with filler, swelling can be marked for several days and changes the shape of the area until it settles.
  • Weakening of a neighbouring muscle after a muscle-relaxing injectable, producing a brow or eyelid droop or an asymmetry between the two sides.
  • Lumps, irregularity or an unnatural contour after filler, which can appear immediately or become visible later as the material settles.
  • Vascular occlusion after filler — material obstructing a blood vessel, which threatens the tissue it supplies and is a medical emergency.
  • Delayed reactions, nodules and infection after filler, sometimes appearing well after treatment.
  • Both treatments are temporary and both are repeated. Neither stops the muscle from moving or the face from continuing to change.
  • Muscle relaxation has no reversal agent and has to be waited out; a dissolvable gel filler can be partly broken down with an enzyme, but not every material can.
  • No outcome is guaranteed, and individual response varies with the area, the anatomy and the material used.

When to Seek Care

  • Sudden severe pain after filler, or skin that turns white, dusky or mottled — contact the treating team the same day.
  • Any change in vision after an injection on the face — seek emergency care immediately.
  • Fever, spreading redness, or a painful swelling that is worsening rather than settling.
  • A lump that is increasing, or skin breakdown over an area that has been injected.
  • Difficulty breathing, or swelling of the lips, tongue or throat — seek emergency care immediately.
  • A droop or asymmetry that is not improving as the treatment fades, for review and possible adjustment.

References & Further Reading

  • American Society of Plastic Surgeons (ASPS) — injectable and dermal filler safety guidance
  • National Institute for Health and Care Excellence (NICE, UK) — relevant guidance on non-surgical cosmetic procedures
  • Cochrane Library — systematic reviews in injectable facial aesthetics
  • Chinese Medical Association Plastic Surgery Branch — clinical guidance

Medically reviewed by Ke He, MD (何锞), Deputy Director & Head of Skin & Laser Aesthetics. Last reviewed: 19 September 2026.

This page is patient education, not medical advice, and it does not cite individual studies. Discuss your own case with a qualified clinician. To arrange an assessment at Chongqing West District Hospital, see Contact & Consultation.