Mouth ulcers, also called canker sores or aphthous ulcers, typically last about 7 to 14 days and usually heal on their own without scarring. Minor aphthous ulcers, the most common type, disappear within 1 to 2 weeks. Major aphthous ulcers, which are larger and deeper, can take several weeks or even months to heal, sometimes leaving scars. Herpetiform ulcers, small clustered sores, usually last 1 to 2 weeks. If a mouth ulcer lasts longer than three weeks, medical advice should be sought as it could indicate a more serious condition. Factors like stress, injury, certain foods, nutritional deficiencies, and underlying medical conditions can affect healing time.
