What this site is for
This is patient education about the fold that runs beside the mouth, published by Chongqing West District Hospital, a tertiary general hospital in Jiulongpo District, Chongqing. It is a concern guide rather than a procedure page: it answers why the fold is there, whether it needs treatment, and which of several paths applies. The treatments themselves and the anatomy they work on are explained on the procedure and authority pages of this cluster, and repeating them here would help nobody.
The distinction the site is built on
A smile line is a mixture of movement, lost volume and descent, and the three parts answer to different treatments. Movement is the muscles beside the mouth folding the skin; volume is the fat lost from the cheek that used to keep the fold flat; descent is the cheek pad having slipped downward so that the crease is present at rest. The proportion differs between faces, which is why two people with equally deep lines are not necessarily the same problem, and why a treatment chosen from the depth of the line alone is chosen without the information that matters.
What it deliberately does not do
It does not name products or brands, quote prices or dosages, or promise a result. It does not present a cream as an alternative to treatment for a fold made by a muscle, or a home device as a substitute for the rung that reaches the mechanism. It does not describe surgical technique, because that belongs to the pages covering the treatments. And it does not treat a fold that has appeared on one side only, that has come on over weeks, or that has arrived with weakness, numbness or a mouth that no longer closes properly as an appearance problem at any point.
The limits of a website
Nothing here can tell you how much of your own fold is movement, how much is lost volume and how much is descent, or whether your smile would tolerate the muscles beside your mouth being quieted. Those depend on seeing the face in repose and mid-smile, on light directed across the cheek, and on a history that includes weight change, dental treatment and previous injections. Use this site to arrive at an assessment with better questions, and treat any answer you receive here as general information rather than as advice about you.