You might know this already, but just in case... Calcium, and even better a calcium pill with magnesium, is supposed to relax the tension in your jaw.
You can find different recommendations on line. Drinks, things using the powder variations of calcium, etc. along with jaw exercises. *Cereal with warm milk is always my favorite, along with a supplement. Something you don't have to chew a great deal is always nice*
When tension builds to an extreme one Soma works well too. Lol