1. Changes in moles
Check your body regularly for suspicious changes in your skin moles. These changes are often the first signs of skin cancer and early detection has a very significant impact on the effectiveness of the treatment.
If you have moles that your primary doctor considers dangerous, you should map them and get a clear sense of their shape and color (use your smartphone to keep a photographic record). Follow the American Cancer Association guidelines for a self-diagnosis: the ABCDE, a mnemonic technique that helps you search visual clues for early skin cancer detection.
Asymmetry: check for moles with weird shapes, or where on half is different from the other.
Border: check for any irregular, ragged, or notched edges.
Color: check for color variations and differences in shading.
Diameter: check for big moles (a good rule of thumb is: if its bigger than a pencil erases, you should see a doctor).
Evolving: check if your moles change in shape, size, or thickness.