In my defense, you should see this guy’s handwriting. It’s — or was — a glomus tumor.

Glomus tumors are relatively uncommon benign neoplasms that differentiate to become modified smooth muscle cells called glomus cells.

And

The exact incidence of glomus tumors is unknown.

And

Patients with solitary glomus tumors usually have paroxysmal pain, which can be severe and exacerbated by pressure or temperature changes, especially cold.

And

The treatment of choice for solitary glomus tumors is surgical excision.

And elsewhere:

Glomus tumor is a rare and benign vascular tumor. The normal glomus unit is a neuromyoarterial apparatus that functions to regulate skin circulation and is found subungually, on the finger tip pulp, on the base of the foot and the rest of body in descending order.

And:

Clinically, glomus tumors are characterized by a triad of sensitivity to cold, localized tenderness and severe intermittent pain. The pain can be excruciating and is described as a burning or bursting.The exact cause of the pain is not completely understood, but nerve fibers containing the pain neurotransmitter substance P have been identified in the tumor.

And

Treatment of glomus tumors consists of surgical excision. Repair of the nail bed must be performed after the removal of subungual lesions. Relief of pain is usually intermediate after surgery.

Some Wiki links: Glomus body, glomus tumor, and neoplasm.