Mouth ulcer. Idea of what is going on?

My mother is suffering from mouth ulcer and it is not curing completely . It is coming back again . She told that she drank hot water( higher temperature ) accidentally and swallowed it . After that only it started. When she got mouth ulcer ,we consulted a doctor and she prescribed some antibiotics for mouth ulcer . But she forgot to  mention about  hot water to first doctor . After 2 weeks we consulted an ent and she revealed the hot water story . Again doctor did a throat endoscopy and she confirmed some redness is in the throat and probably due to acidity . She prescribed some acidity medicines and she took that for 2 weeks . Also she used to. Gargle betadine and salt water . But two days back she got another white pimple kind of inside the mouth . Attached the pic and highlited the white bump. Also attached a bump in tounge . Also she got another red bump in tounge . Is it due to hot water she is getting these again and again ? We are not having a clear idea of what is going on ?