<s>[INST] Hi I have had a small yellow blister on my small palate now for about three months and my doctor said its nothing but my dentist said its because my immune system was low as I had been on triple antibiotics because I have h pylori . That was about 5 weeks ago and it still hasn t changed really, maybe a tiny bit smaller but that s all. Appreciate any help thank you. I am a 25 year old male and it is only sore if I drink hot things but even then it s not bad [/INST] Hello Welcome to HCM I would like to tell you that canker sore can be due to:- -stress problem -vitamin deficiency -trauma or injury while brushing It can be treated by:- -multivitamin treatment -taking natural milk -avoiding spicy food -applying dologel Consult your dentist for further query. Take Care Regards Dr.Neha </s>