It sounds to me like he has learned a new game, or is cutting more teeth. Quite possibly both.
I would feed him cereal, or baby food, or whatever (My kids are mostly teens and I don't remember what they ate at 7 months!)
If he plays with the bottle by gnawing on it, take it away and give him something to chew on.... Or maybe give him something to chew on FIRST and if that doesn't satisfy him THEN offer the bottle.
Or, if the bottle isn't an option, maybe he would become more interested in the sippy cup.
Sorry I can't be more helpful, but those are my initial ideas.