Ulcer, unlike the usual kind

[Dorsetmama]

My DS gets ulcers. We all do, frequently. Just susceptible to them as a family.
He has two in his mouth, one is the usual flat kind, and one is raised like a blister, but its kind of hard. Doesn't seem to be as painful as the normal ulcer.

Any ideas?

Could it be hand foot and mouth?

That did cross my mind, ill check the rest of him when we get home from school.