All sorts of things like reactions to toothpastes, mouthwashes, chewing gums etc as well as fungal infections and many other things.
so any ideas on what else this could be.
This could be oral herpes but it's also quite likely to be something else going on. At this point it's best to go and be seen and get these properly evaluated. DO NOT ACCEPT A VISUAL DIAGNOSIS OF HERPES - if they suspect it's oral herpes, ask them to please confirm it with a lesion culture and typing.