What is this lesion and describe it ?

Ulcer = Loss of surface tissue caused by a sloughing of necrotic inflammatory tissue: the defect extends into the underlying lamina propria. Appears red around the outside and white in the middle.(E.g., Aphthous Ulcer – Usually appears on the mucous membranes of the mouth. Is painful and typically heals spontaneously within 7-10 days.) Ulcer: an open wound that develops on skin as a result of injury, poor circulation or pressure Aphthous Ulcer: small, shallow lesions that develop on soft tissue, whitish yellow, red border