My husband has had dogs his whole life and I told him about Tucker and asked him what he would do ....he said the same thing Schatzie said ...and added that I'm an alarmist

and would go to the vet for a mosquito bite....I told him it would have to be a pretty BIG mosquito bite but yes I probably would...so don't mind me - I would call just to inquire if they have an idea what it could be though...
I really hope your Tucker will be be ok ... if he's eating and drinking ...that's a great sign of feeling good ...and whatever it is ...maybe it's just draining ?...Please let us know OK ?