Why is my mouth asymmetrical when I laugh? (Photo)

Whenever I smile with my mouth open or laugh, or just open my mouth wide in general, my left bottom lip seems to pull down showing the left side of my bottom teeth and making my whole mouth look asymmetrical. I have no control over it. Is this to do with muscle weakness on one side? I have had TMJ in the past and wonder if it could be linked to that? What can I do to correct this as its really affecting my confidence.

No doctor answers yet