I have a black spot eating my toe. what should i do?

Go to dermatologist: The incidence of melanoma, while still relatively rare in the foot, is becoming more and more frequent. Because melanoma is such a dangerous disease, it's important you get this thing looked at asap.

Eating your toe?: Necrotizing tissue?? Need immediate eval.

See doctor asap: or go to ER. Are you diabetic or do you have peripheral vascular disease.