Botox is a neuromodulator which works by temporarily blocking the ability of nerves to tell the affected muscle to contract. This can be used to our advantage by blocking the ability of specific muscles to move. This allows the muscles to relax and the skin over the top to repair itself and reduce or eliminate wrinkles.
Botox can be used to treat lines in the area at the corners of the mouth, which is considered an off-label use. Specifically, we are treating the depressor anguli oris muscle. This muscle pulls down on the corners of your mouth. It is one of the muscles that contract when you are frowning.
When injected correctly, it can allow the corners of your mouth to elevate a few millimeters and benefit Resting B**** Face (RBF). I really do not like that term but I do have patients specifically ask me about it. The corners o of the mouth turn down as we age and we lose volume in our cheeks and around our mouth. Botox is not always the only answer as sometimes fillers may be needed or even surgical intervention in some cases.
Botox can also help with the marionette lines (puppet lines). These are the lines that form at the corners of your mouth and run down to the chin. This can also be associated with RBF. This is also part of the aging process and is secondary to aging skin and loss of volume in the face. In the early stages, Botox can be beneficial by itself but as above, it may also require volume with dermal fillers or even surgical intervention.
If injected correctly, Botox can significantly improve the marionette lines and a downturned mouth. If injected incorrectly, there are multiple complications that can occur, including affecting your speech and your smile. It can make your smile look asymmetric and your speech slurred. If bad enough, it could lead to you biting the inside of your cheek. I recommend that you use a very highly competent injectionist when treating this area of the face with Botox.