Hi, I'm 25 Years Old And My Knees Are Congenitally

Hi, i'm 25 years old and my knees are congenitally dark since the very young age I can remember. My complexion is fair and my thighs and legs have normal fair skin so the color difference between leg, knees and thighs are high. I have tried remedies, whitening oil treatments and they didn't work out. I'm even considering laser treatment or skin grafting. The dark knees are really annoying me. Please tell me what I should do to eliminate them in minimum time. Thank you.