Thank you so much for the concerns and comments.
It turns out instead of one tooth being pushed at a time, it was two molars being pushed out on one side.
We were playing and I guess that loosed up what I thought was one tooth and he was going crazy trying to get it out. He kept trying to chew it out and then even used his paw to somehow 'help' his efforts. I tried to see if I could help him, but he refused. I just sat there and tried to calm him down. . then to my surprise, two little teeth fell out. Those fell out yesterday and that seemed to ((possibly)) eleminate the jaw trembling.
He has the teeth on the other side being pushed out too, so I hope they come out soon so he won't be uncomfortable.