K.J.
My son is 6 1/2 months right now and he drooled like crazy for about a month 4-5 months old. He still has not cut a tooth but it is part of their developing the swallowing on their own process etc. It does pass, and then when they are teething I have heard it can start again. This sounds like mouth exploration is starting. Give them things that they can put in their mouth a nuk, teething toys etc. I have heard that at any age children can begin cutting teeth.