My husband has been suffering from mouth ulcers on tongue and under the lips area from past 6 months. Initially vitamin b12 complex was deficit and he was undertaking injections for that. In between when the injection dose was over he used to get ulcers again. After 4 months he got tested and b12 level was good 700+ still he got the ulcers. He doesn't have constipation problem or any kind of stress. Still these ulcers appear repeatedly. It's not in the same area in mouth. It heals once completely and a new one appears next. Please advise the course of treatment.