A recurring mouth ulcer should always be followed up and investigated further, initially by your own dentist and sometimes by your own doctor and if necessary by an expert in oral medicine. A reassuring aspect of your ulcer is that it appears to heal; this differentiates it from a more serious ulcer that does not heal. A very important aspect of the investigation of your ulcer is to look for predisposing factors. There may be a sharp tooth, filling or denture which is traumatising your tongue. Alternatively, you could be having a reaction to some foods containing certain preservatives, or you may have an iron deficiency. Your own medical doctor will test you for the iron deficiency. Tell your dentist about your ulcer on your next visit and ask for advice about relieving symptoms, if these are a concern to you.