Pipp's right.
Also, the tooth grinding is a sign of pain. It may mean that he should get some more pain meds, like Metacam (meloxicam). It's like ibuprofen in its pain-killing abilities, but it's better than nothing.
You can also gently apply ice to the area to help with swelling. We did 10 min 3x a day with Benjamin. Put some kind of cloth between him and the ice pack. Also, offering something warm may help soothe it. A pop bottle filled with warm water is a cheap way to do this, as is a sock filled with dry rice and microwaved for 1-2 min.
