Is my overactive mentalis muscle caused by jaw clenching?

There may be a slight association between the mentalis muscle and masseter muscle depending on the person and how they move the muscles in their face. If you are considering Botox to treat this area, an experienced injector would administer Botox into the mentalis muscle. 

I am a firm believer that dimpling of the chin is genetic and due to the way the muscle connects to the skin.  If you move your lips or lip corners enough, you may be able to change the way the dimpling appears.  I do not feel it is due to jaw clenching at all.  I frequently treat the muscles that control the jaw chewing/clenching (masseter) and do not see the chin or mentalis change at all.  Best, Dr. Emer.

While being a "clencher" wouldn't cause the mentalis to be over active they could be related because the same nerve (the facial nerve) controls both. Clenching can be habitual, but it can also be related to over activity of the masseter muscle. Both an over active masseter and mentalis muscle could be related to the nerve being overly excitable.You may find relief of both of these problems with a Botox injection. I would suggest consulting a local plastic surgeon to be properly assessed.

Jaw clenching can definitely lead to wrinkles and jaw dimpling (orange peel/golf ball chin).  The good news is that Botox and others such as Dysport and Xeomin can help to fix this.  While the results only last for 3 months or so, many times the habit is 'broken' while they are under effect and the clenching/dimpling isn't quite as obvious after this.  The important thing here is to go to someone who is an absolute expert in this.  This is not beginner's level or even intermediate level injection technique.  It is a full-on expert level job because if it is done incorrectly (or sometimes even if done correctly) there can be asymmetries and lips can droop on one side or both.  So this is somewhere that you have to go to someone who really knows their stuff or you could have 3 months of issues.  Good luck!

Botox can be expertly administered into the mentalis to soften the "orange peel" appearance certain clients get from contracting that muscle. While jaw clenching typically builds the masseter muscles up it could certainly contribute depending on your anatomy. The great news is you can safely inject masseter muscles to not only soften the jawline but also reduce facial bulkiness that can build up from clenching. The mentalis itself requires very little Botox to achieve a softer appearance. I would recommend going to an expert injector in your area and getting assessed to see what you would be a candidate for.