An oral fissure is a small tear in the lining of the mouth. Some common synonyms for this condition include mouth sores, canker sores, or cold sores. Other related terms include ulcerations, lesions, and blisters. Patients with oral fissures may experience discomfort, pain, and sensitivity when eating or drinking. Treatment may involve over-the-counter pain relief medications, topical ointments, or antibiotics if the cause is infection related. In some cases, oral fissures may be a symptom of an underlying medical condition, such as an autoimmune disorder or nutritional deficiencies. It is important to seek medical attention if symptoms persist or worsen.