I am 20 years old. In last 6 months my face skin has turned much darker all of a sudden. My face skin was 2 shade lighter than body but now it's 2 shades darker than a body. Even when I shave it becomes more darker. Now I have stopped shaving. I went to dermatologist he gave a sunscreen and salicylic acid face wash but after month usage my face went more darker I used use sunscreen for last 2 years .i used it before 30 min going out. But the doctor gave me new suncros sunscreen but after everything there was no change.