Sounds like a razor rash - get yourself some cream like E45 and it should help, and after razoring the area put some alvera Gel on it - helps keep it cool and can help stop the rash coming up in the first place. Make sure you clean very very well or you could get Infected hair follicals in that area (bacteria on the skin causing Spots filled with puss and they itch and hurt and can be 5mm-10mm in diamiter)
Go to a doctor, you might have used a old infected razor. Take necessary treatment soon.