I have a mark on the side of my penis and it seems to be growing. its brown, flat, & does not itch. i know it's from masturbation. i want it gone help?

Iron pigment: Most guys have a mark like this during their teenaged years. It's just past where you grip yourself, right? It's hemosiderin from red blood cells released from microtrauma. It's not a problem, but it's gone in a month or so if you vary your technique when you're enjoying yourself, and use less pressure / grip strength. This will prepare you better for different possible partners.