Re: Red bumps around groin region
It sounds like it's probably a minor yeast or bacterial infection. You might only get them from not washing off after sex before going to sleep.
An anti-microbial soap could help too. I like Neutrogena T/Gel, which is actually sold as a shampoo. It's a good antimicrobial and it's pretty drying, which is usually good for that area too.
It helps to prevent yeast and UTIs to consume cranberry. You and your girlfriend might have cranberry once a week or so to keep from worrying about having given the other yeast or a UTI.
Finally, there's certainly some possibility this could be an STD too. I'm really not trying to worry you, but you shouldn't rely too much on advice like this (based on your very brief description of the problem and my lack of any medical qualifications). Basically, peer advice like this could be very misleading.