Hello Mouth ulcers,In most cases, the cause of this kind of ulcers is not known. However, stress is an important risk factor for this. Some may be causes by certain viral infections. Other triggering factors include feeling anxious, certain foods, hormonal changes and quitting smoking. There would be certain local anesthetic gels which can be used for oral application, which help in relieving pain caused by these lesions. You can discuss this with your family physician Avoid eating foods that irritate your mouth which include acidic foods(orange juice, soda etc) spicy foods. Maintain good oral hygiene so that secondary infection may not happen. But, sometimes these kind of ulcers will be very resistant to treatment and are recurrent. Usually, these lesions should heal within 10-14 days. Use of antiseptic mouthwash helps faster healing and less chance of recuurence. Hope I have answered your query. Take care