It sounds like you have tinea versicolor
. This is a superficial fungal infection
common in adolescents and young men, but can happen in anybody. I recommend trying an antifungal cream (eg. ketoconazole
, or itraconazole) AND if you can get ketoconazole shampoo (brand name Nizoral), you can use it as a body wash to promote healing. It does sometimes take a while to eradicate and often gets worse in appearance when you tan or spend a lot of time in the sun.
If topical treatments fail, you may have to see your doctor for oral antifungal