my whole body is light skinned, but my ball sacs some underneath parts of my penis are kinda dark, i dunno why. i tried washing it thoroughly and scrubbing it but there's no change. my girlfriend wants it to be the same skin tone with my whole body so it will look cleaner. is there a spa or a derma that can lighten such things for guys? is this deep sitted-dirt or is it just natural for light-skinned guys to get dark in those area as girls can darken their armpits?