Since melanoma can spread quickly, do not hesitate to have your skin checked by your doctor. Learn how to do a monthly skin self-exam. There is an ABCD guideline for watching your skin. A stands for asymmetry. That means that one half of your mole is different from the other half.
B stands for border.
If the border of your mole becomes irregular, have it checked. C is for color. Your doctor should check changes in the color of your skin. D is for diameter. The diameter is the length of a mole from any end to the opposite end.