Melanoma is the least common type of skin cancer. Still, it is the most deadly because it can spread if not caught early. Melanoma symptoms include a change in the shape, size, or color of a mole, but melanomas can also look like a bruise that doesn't heal or a dark streak under a finger or toenail. Excess sun is linked to melanoma risk. However, melanomas can also occur on skin not exposed to the sun (such as inside the mouth).
Your chances of getting skin cancer are based on heredity—what you’re genetically predisposed toward—and your own tanning and burning history. Answering these expert questions will give you a general idea of how vigilant you have to be.