M.M.
Two suggestions that have worked for me after I thought I was never going to get my life back from TMJ.
1- Dr. David Toney in Allen fit me with a night guard that has almost completely relieved the pain - and it was bad. Dr. Toney is a fabulous dentist. ###-###-####
2- Once the pain gets stabilized, go to Dr. Russell in McKinney. Phone: ###-###-#### This sounds goofy, I know, but it eliminated the last of the pain I had from TMJ. Dr. Russell is a chiropractor and he has a male massage technician that is excellent with facial massage. Don't let them put you with the other massage techs, they are good, but not as skilled as the male is with facial work. It's fairly reasonable - like $40 a treatment. I went 3 times and the facial massage was amazing for eliminating the pain. I had never used a chiropractor before and wasn't sure about them, but they have made a huge difference for me.
If I don't wear the night guard, though, it will all come back, but these two things together have kept me pain free.
He does need to see a dentist. In the mean time put ice on it and take aspirin or motrin. That's about it until a doctor can get to him.