Problem after shaving?

I lost a bet a couple Of days ago, and had to shave my pubic hair. It's been maybe 3-4 days, and where I shaves there's a rash and what appears to be pimples. And it hurts alot. Anyone know why and how to stop/prevent it? I have to keep said area shaved for a month, and I don't want this happening again once or if I fix it.