Need tips on how to take care of my skin…?

So throughout the years I have crawled on the carpet and my knees got rug burned and are all dark now. Do any of you awesome people know what I can do to make my skin regular and lighter!? I really need the help, it looks like my knees are all bruised up when I where shorts when there really not, it's ugly. Also does anybody know any ways to help me clear my skin from pimples and blackheads? Any treatments, creams, face washes you recommend? Thanks!