Bumps can be so many things, and it's impossible for us to tell you what they are. It could be anything from a fungal infection to warts to molluscum to eczema to about a dozen other possibilities. You need to see your doctor, who can examine it and tell you what it is.
If you don't have a regular doctor, find an STD clinic near you (I'm not saying it's an STD, but they should be able to help anyway), or go to an urgent care clinic.
Let us know what happens.