My razor burn won't go away?

When I began shaving I didn't know about razor burn, so I shaved like everywhere except my back and pubes. Now it's like a year later and I have razer burn where hair doesn't even grow! It's on the side and bottom of both my armpits and on both the insides of my thighs. I started putting this ointment called A+D Ointment on it because it's for Chafed Skin and abrasions and stuff, but it's still not going away! How do I make it go away and stay away?