Hello, It may apthous ulcers or tobacco pouch keratitis or lichen planus or mucosal cyst etc. Until examination is done it is difficult to say what it is. Take vitamin A capsules daily use tablet Pantoprazole before breakfast for one week. Check for surrounding dental malocclusion or malunion. Use dentikain gel locally if you have pain.If symptoms not improved please consult your doctor he will examine and treat you accordingly. Hope I have answered your query. Let me know if I can assist you further.