Thanks for using Health Care Magic. Read your query. Recurrent mouth ulcers is usually due to some factors it can be due to Stress or anxiety related , Nutritional deficiency , vitamin deficiency , immune disregulation , hormonal influences . If I was her treating dentist ,I would advice her to apply mucopain/dentogel gel two or three times a day. Do salt water gargling for a while. Avoid spicy food for a while. It will subside on it own gradually within a week or two. Avoid stress and have a nutritious diet .Multi-vitamin supplement can be taken. If still persistent, consult an oral surgeon. Hope this was helpful. Thanks and regards.