In short. The labial arteries vary in course and depth, the lip moves constantly, and the vermilion border forgives a wrong plane later than anywhere else.
Key points
- A named person who will assess you if the tissue changes colour, a plan for reaching them out of hours, and immediate access to the treatment that breaks down the reversible class of material.
- That class is used in the lip almost always, and the choice is partly a choice about what is available if something goes wrong.
- A clinic that cannot describe that arrangement clearly is not the setting for this treatment.
The lip is a small area and the risks of injecting it are not small in proportion. Three of them belong to this site specifically: the arteries that run inside the lip, the border that shows a wrong plane early, and the movement the material is subjected to for as long as it lasts.
The labial arteries
The upper and lower labial arteries are branches of the facial artery and run inside the lip, classically in the plane between the muscle and the mucosa. Their course and depth vary between people and are frequently not the same on the two sides: a vessel close to the surface in one lip lies deeper in the next. Material that enters one of them can travel, and the tissue it reaches is starved of blood. The mucosa and the skin can be lost, and in rare cases material reaches the circulation around the eye and vision is affected. This is time-critical rather than cosmetic, and the outcome depends on how quickly it is recognised and treated.
The border
The vermilion border is a junction between skin and mucosa, and it shows an error that a fold of skin would absorb. Material placed too superficially produces a visible ridge or a bluish tinge through thin tissue, and repeated placement across the border widens it, so the edge stops being an edge. That change is not corrected by adding more material.
Movement, and what it does to the material
The lip is deformed by speech, eating and expression many times an hour. Material inside it is worked on continuously and can shift within its plane, which is why lumps, nodules and asymmetry are described here more often than in a static area, and why a result can look right at rest and too much on smiling.
What has to be ready before the first injection
A named person who will assess you if the tissue changes colour, a plan for reaching them out of hours, and immediate access to the treatment that breaks down the reversible class of material. That class is used in the lip almost always, and the choice is partly a choice about what is available if something goes wrong. A clinic that cannot describe that arrangement clearly is not the setting for this treatment.
What is ordinary, and what is not
Bruising, tightness, patchy numbness and small lumps in the first fortnight are ordinary. A reaction appearing weeks or months later, sometimes after an unrelated illness or a dental procedure, is less common and needs assessment rather than waiting.
Emergency signs, during or after
- Severe pain out of proportion to the injection, or pain that worsens rather than settles.
- Tissue turning white, grey, mottled or dusky anywhere on or around the lip.
- Any change in vision, including blurring or a patch of lost sight.
What can be undone afterwards, and what cannot, is set out in What Cannot Be Undone After Lip Filler. The wider emergency picture is covered by the filler complications pages and by quality and surgical safety.
Frequently asked questions
How common is a vascular complication in the lip?
It is uncommon, and frequency is not the point. The labial arteries run inside the lip in a course that varies between people and between the two sides, and material entering one of them can travel. The outcome depends on how quickly that is recognised, which depends on what was arranged before the injection rather than on how likely it was.
Can lip filler bring on a cold sore?
Yes. An injection commonly reactivates the virus in someone who has had cold sores before, and the lip is the usual site. It is worth saying so at the assessment rather than afterwards, because it can be anticipated and because an active cold sore is a reason to postpone treatment rather than proceed through it.
Does using a blunt cannula remove the risk?
No. A cannula reduces the chance of entering a vessel directly and covers more of the lip through fewer entries, and it still reaches the plane the arteries occupy. It changes the odds rather than removing them, and the lip is a site where the arteries are variable enough that no instrument makes the question go away.
Risks & Limitations
- Vascular occlusion is a time-critical emergency, and the lip is a small area whose arteries vary in course between people and between the two sides. Severe pain out of proportion to the injection, or tissue turning white, grey, mottled or dusky, requires immediate assessment.
- Every filler result is temporary, and the lip fades unevenly: the border often loses definition before the body of the lip flattens. Maintenance treatment is required to keep a result continuous.
- The lip tolerates very little added volume before the change reads as treated, and only the reversible class of material can be broken down at all. A stretched vermilion and a border that has been filled across do not revert when the material goes.
- Lumps, nodules, asymmetry and delayed inflammatory reactions can occur, and an injection commonly reactivates cold sores in someone who has had them before. The lip is the most mobile injected site, so material inside it is being deformed continuously.
When to Seek Care
- Any change in vision, including blurring or a patch of lost sight — seek emergency care immediately.
- Severe pain out of proportion to the injection, or pain that is worsening rather than settling.
- Tissue turning white, grey, mottled or dusky anywhere on or around the lip.
- Swelling that is increasing after the third day rather than settling, or fever with spreading redness, warmth or discharge.
References & Further Reading
- American Society of Plastic Surgeons (ASPS) — procedure and safety guidance
- National Institute for Health and Care Excellence (NICE, UK) — relevant guidance
- Cochrane Library — systematic reviews
- Chinese Medical Association Plastic Surgery Branch — clinical guidance
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.