What Causes Small Cysts In Groin Area?

I am a 22 yr old male and last summer I worked at an ammunition plant. It was very got and I thought I had what looked like heat rash around my groin area. I tried calamine, oatmeal baths, medicated powders, and even antifungal creams and even rubbing alcohol. It's months later and now I have what looks like small cysts under my skin in the same area. Some of them have puss if I squeeze them and some don't do anything. I want to know if this is serious.