People often miss things, or mistake them for something else. My buddy thought he had a mole on his ear until it turned out it was aggressive melanoma. They r

People often miss things, or mistake them for something else. My buddy thought he had a mole on his ear until it turned out it was aggressive melanoma. They reconstructed his ear and took out some lymph nodes, and 2 years later it came back in his lung. Fortunately he enrolled in a clinical trial of immune based chemo, so he only lost his thyroid and adrenal glands. How likely is it that you'd notice melanoma on your scalp or back?