For years, I've noticed that my skin does not heal properly. I have stretch marks that still have a lot of pigment even though I've had since elementary school (I'm 18 now). My tans take forever to fade. Whenever I get acne,it always turns to a red mark that darkens to a brown mark. I've had the same ones for years. Also, when I get even a little cut, it'll leave a mark behind. What is causing this and what I can I do about it? It's really bothersome and it keeps me from looking my best.