u/User_Goes_Here

Ive noticed the pass few days that when I wake up my kitten will have a wet upper lip and his tongue will be slightly out. It goes away pretty quickly and he has no issue with eating hard or soft food or playing with his sister. I explained it to the vet yesterday and showed them a pic but when she examined him she couldnt find anything out of the ordinary. He sleeps pretty deep and heavy could he just be drooling in his sleep? Anyone have any ideas what it could be? Attaching a pic of him this morning and a pic of how he normally looks.