Hello Doctor, My skin is very dark near my butt and inner thighs compared to my rest of the body. my butt becomes dry most of the time. i could also see lot of dead skins on my butt and black marks on my waist. i think this dark mark on my waist is because of wearing tight pants. i apply moisturizer on my butt and waist when it becomes dry. How can i get rid of this dark skin on my butt and my waist? i am 24yrs female