Pigmented Oral Lesions: Clues to Identifying the Potentially Malignant Consultant360 05 May 03 Eng Common Causes of Dark Spots on Gums Smilepoint Dental Beaumont TX An oral melanotic macule is a harmless dark spot found on the lip, most often the lower lip, or inside the mouth, either on the gums, inside the cheek, or on the roof of the mouth. An oral melanotic A Problematic Oral Pigmentation: Deep Penetrating Nevus