Lip filler: the questions to ask yourself first

What proportions suit your face?

Beautiful lips are not necessarily big lips. In one study, faces modified by computer were ranked by several hundred people. The proportions judged most harmonious combined, seen from the front, an upper lip covering about half the surface of the lower lip. The reverse, an upper lip twice the size of the lower one, was judged least harmonious. Faces that moved away from these markers were found less attractive.

These markers have a limit: the study looked at the faces of young white women. They do not necessarily apply to every origin or every age. That is why I measure your own face rather than apply a rule.

What exactly do you want to change?

• The contour: a lip border that has faded, a less defined Cupid's bow.
• Hydration: hyaluronic acid holds water in the tissues. In small amounts, it is used here to restore a softer look, not volume.
• A slight asymmetry between the two sides.
• A very thin lip, with a measured addition of volume.

A marked asymmetry of bone or dental origin calls for a different approach.

How far should you go?

Overcorrection is the first pitfall. The so-called "duck lips" look, with an overfilled upper lip dominating the lower one, reverses the proportions judged harmonious. Lips move constantly: such a mobile area may be more exposed to the product shifting, especially if too much is injected, too quickly or under too much pressure. It can then migrate out of the intended area, although this remains rare with hyaluronic acid.

The second is accumulation. With repeated touch-ups, the eye gets used to it and ends up finding normal what no longer is: this is perceptual drift, which I discuss in another article. Part of my role is to say when nothing should be added. The first time, we always do less: we meet again around day 15, with the same photographs, and add more if needed.

Do you have an event coming up?

In the following days, the lips often swell, sometimes with a bruise. In one trial, 58% of people had swelling and 44% a bruise, mostly mild; these reactions resolve on their own. Avoid planning the injection just before an important event: the result is judged at the check-up, not the next day.

Do you get cold sores?

Tell me before the session: an injection into the lip can trigger an outbreak. An international expert consensus then advises preventive antiviral treatment, which I prescribe in advance. If a cold sore is active, the session is postponed until it has fully healed.

Do you know the warning signs?

Very rarely, gel can block an artery of the lip. Unusual pain, skin that turns pale, mottled or purplish, sometimes small pustules in the following days, should prompt you to call the practice without delay: treatment is urgent, and hyaluronidase, the enzyme that dissolves the gel, is always available at the practice.

The whole procedure and its risks: lip injection.