My dog is an 8 year old Jack Russell. I took him to the vets last Thursday as he is recently having difficulty closing his mouth; it seems like his bottom jaw hangs open and he cannot keep water or food inside very well either. His breathe is very fowl smelling too and there is a lot of saliva floating in his water bowl when he tries to drink. He can close his mouth though, just it is open and his tongue hanging out. The vet performed some blood tests and prescribed some antibiotics, however there is no improvement so far... any help would really be appreciated as I am very worried now. It was never like this before.

You need to find another vet, preferability one that is an emergency hospital.