22m skin spots scared of CANCER

Hello, a half a year ago started appearing some spots on my arm (around triceps to be precise) after that it started appearing in armpit. After that one spot apeared in abdomen.(m. Obliquus externus abdominis to be precise) And the thing what scares me most is it doesn't itch, hurt or something. Spots looklike a got burned I’m nonsmoker 175cm,74kg. Can anyone assure me its not cancer or what it is?