If I know I am going to be in that type of situation, I often take a food storage thermos with at least 1 hot, damp wash cloth in it. I can then wrap them or hold them on my TMJ area to help keep it warmer...helps with cold hands and feet, too.

I have TMJ and nothing really helps for me. I try ice, heat, lidocaine ointment, muscle relaxers (those help a tad), IBprofen. I used to get trigger point injections in the jaw joints, but the doc who did them moved and my current doc doesn't want to do those. I guess it is too scary when it comes to my face LOL. I do hope you find some relief.

Temporomandibular joint @A MyFibroTeam Member
https://www.webmd.com/oral-health/ss/slideshow-...

Rice bags too!

I use wheat bags.