treatment works drinking orange juice, anything with a lot of vitamin C!!!!
Sounds like canker sores. I got them only as a child. My folks put Campho Phenique on them, but I think they just go away with time on their own, like a pimple. They are hard, but they do look like a bubble. Annoying. Try googling canker sores and see what it says.
Next time you get one, check in with a dentist, they can tell you what it is and type of treatment. Most common are mucoceles, but it could be any number of other things.
I just started getting a single one of those simple cyst on my inner lip filled with clear fluid. I pop it and in three days a small one comes back, about 0.3-0.4 cm in greatest deminsion. What are these??? Causes, treatments?