hello, the condition u had described seems to be oral ulcers.. most common are recurrent apthous ulcers- it occurs mostly in movable mucosa of mouth... and is associated with stress, erratic eating habits and schedules, etc.. and other types of ulcerative lesions includes-traumatic ulcers,nutritional deficiency stomatitis, herpetic stomatitis, infectious mononucleosis, lichen planus.etc.. a proper clinical examination,history and exfoliative biopsy will confirm the diagnosis..if you have any skin lesion which you forgot to mention in ur query then may be its mucosal presentation of skin lesions.. if your mucosa being traumatised in the affected area by any of your sharp tooth or restoration then its grinding will solve the problem.. recurrent nature suggests that your body is having hard time dealing with it due to compromised defence system.. for pain in ulcers use any local anaesthetic gel prior to meals, then have antiseptic gel or mouthwash after meals to prevent infection in eroded surface of lesion, increase your vitamin B and C intake either dietary supplements in form of fruits/medicines.. this will help you.. in apthous ulcer case stress, smoking, erratic eating schedules should be avoided.. consult oral medicine and diagnosis specialist if the lesion doesnt resolves in 7days of treatment.. or it recurrs again.. take care.