Sudden Drooling, A LOT of it

Last night my Dalmatian started drooling when we were eating dinner, I just thought it was because of the food. After we were done, he started making drool spots on the couch. I woke up and he made a bunch of drool puddles in his sleep and he kept drooling all day. We took him to the vet and they couldn't find anything wrong and said he might have eaten something he wasn't supposed to. He is still doing this 24 hours later and I'm starting to worry. The vet also said he's too old to be teething because he's 1 year and 3 months old. Has anybody else experienced anything like this?