I shave my butt and now it looks really irritated and hurts when I shave, can the irritation dots go away and how?

Razor burn. This happens when there are a lot of dead skins cells and some bacteria on the skin. Using a dull razor also makes this happen more. Try using cortisone cream for a few days to get the bumps down before you shave again. Don't use this cream all the time, it will cause another skin problem. Once it's better, scrub the area well with soap and water, then shave with sharp razor and shaving cream.