Can one get Botox to soften an overactive muscle in the cheek?

If you have an overactive muscle a small amount of Botox may improve your concerns, however it could also lead to an asymmetric smile.  I encourage you to begin by visiting with a board certified plastic surgeon near you.  After an examination and discussion of your concerns the appropriate treatment can be recommended.

As a neuromodulator, Botox is designed to work on overactive muscles. However, use of the product in this area would be off-label. Another option might be well-placed dermal fillers on the side of the face that requires correction. No matter what treatment you choose, make sure you work with a board-certified dermatologist with expertise in injectable fillers to ensure an optimal outcome from your procedure. 

Thank you for your question! Even though, Botox in this area would be considered off label, it could be used depending on what specific muscle is contributing to the asymmetry. You would want to be assessed by an experienced injector. Best of luck to you!