Well next time you go to shave get the are wet and apply shaving cream. You need a new razor about every other time. I've noticed the single blades work best for me. Then Noe is the part that matters you need to shave in the direction of your hair growth this prevents the bumps. They also sell this cream in drugstores for after you shave your bikini area and it's stops the razor bumps.
Rinse out your pubic area using an antibacterial cleanser and use a fresh blade for every two to three shaves. You can also use a cotton ball dipped in witch hazel to wipe your razor bumps. You can find more from this link http://howtoshavetips.com/.