I have some kind of white spot on my back neck, and it feels itchy when i have a sport and getting hot and sweating, what should i do ? thanks

Cyst : Could be done kind of cyst that may get irritate or inflame.

See your doctor : It is hard to know exactly what is causing your itching and hot sensation for a spot on the back of your neck. Sometimes a white spot with a dark ring is ring worm, an infection that can be easily treated. This can have the discoloration. If you are placing a sweaty towel over this area when you work out make sure all equipment and towels are cleaned after each use. See an md to treat.