What Causes Pus Filled Pimple In The Genitals?

I just popped a pimple like thing on my boyfriend s gentile it was near the crease of the gentile and the balls. It was big bump with a scab when i popped it, it oozed out greenish yellowish and then the rest clear liquid with blood... Should I be concerned about him having herpes or anything? Or could it just be an ingrown hair or maybe even a zit? He doesnt have a family doctor and he s to embarrassed to ask his mom.