Darkness below...

Ok so random question. Im an olive tone skin colored person. my labia is darker.. a lot darker. I wanna know why and I wanna know how to make it my normal skin color. It could be discoloration, maybe too tight of pants or underwear? Idk, but it's been that way since I can remember. I've always been self conscious about it. Im going for my annual paps visit in a week and I'll ask my doctor but I figured I could get an idea here or maybe different types of opinions to ask about to my doctor. Thanks guys!