My mother is experiencing repeated mouth ulcers for 1-1.5 years. We have tried many medications, sometimes the ulcers go away for 1-2 days but appear soon enough. She was experiencing difficulty swallowing also previously but it's better now. Some doctors suggested she had some allergies and gave medications according to that. But nothing worked. I really need some advice on how to diagnose and cure this and who to approach for its treatment. Thank you!