Ok so my kitten has two mouth ulcer sort wounds on her bottom jaw. Does anyone know what the cause is, what it possibly could be and treatment.

I have two pet mice, beautiful boys, they are now approximately now a year and a half old. However earlier this week i notice a little red spot on the bottom jaw of one of them, i thought it may just be one of the old scabs as they recently had mite, which have been all treated and they are...