Oral Melanotic Macule: Symptoms and Treatment Skinsight ORAL MELANOTIC MACULE (OMM) (Also called focal melanosis labial melanotic macule) A benign, localized, flat pigmented lesion of the oral mucosa Caused by a focal increase in melanin production Does anyone know what this black mark on my lip is? Started last August so it's I've had it nearly a year, was living in Spain at the time for 6 months Oral melanoacanthoma and oral melanotic macule: a report of 8 cases, review of the literature, and immunohistochemical analysis