K.B.
Sounds like early molars to me!
My son did this EXACT same thing and about 2 weeks later I noticed a huge molar on one side of his mouth.
If this is the case, get some Hyland's Teething Tablets, and Motrin/Ibuprofen. It kills the pain better than Tylenol/Acetominophen. Try to be patient when he does wake up... its so easy to freak out and get mad out of exhaustion.
Hang in there!