Asymmetrical cheek muscles, what can I do to make my cheeks match?

Your case is somewhat unique and would need an in-person assessment to properly diagnose and recommend a treatment plan. While the area you are referring to is indeed dynamic, there are formulations of dermal fillers today that are specifically designed to move with your face. However, a careful evaluation would be needed to determine whether this is the right approach for you. I advise you to schedule a consultation with an experienced, board-certified dermatologist who will have the expertise to customize a treatment for you to produce the best possible results. 

I believe the intradermal microinjections using Restylane Refyne will help with this issue as would Sculptra Aesthetic. I know it is not what you want to hear but I think it will help.

This is really an interesting case. As it is dynamic it is really difficult to tell from a photo just want is occurring. It could be just a volume loss or more likely the area is bound down. Which unfortunately means you really need someone to closely evaluate the area . I know you mentioned not wanting to use a filler but an experienced injector can really make a difference in this area with a filler. Today there are dermal fillers that are more elastic  and function very well in dynamic areas.

I believe you would benefit a great deal from having Autologous Fat Grafting. Fat grafting will it restore the Lost volume in the face as well as correct the skin from any of the effects of aging. The results of fat grafting should be completely natural and almost permanent. I hope this helps and good luck from New York City, have a look at our website for more information.