My is inflamed?

It's a blister. Young teenage boys tend to get them often because they are new to the whole masturbation experience. So they masturbate on average between 4-6 times a day. Sounds crazy right? Well what else do they have to do. In your case since you shaved your pubs and then masturbated you caused and irritation spot which in place caused a blister to appear. Don't worry you will be ok in the next couple of days when it pops. Just for now leave Mr. Happy alone until the blister is healed. I would maybe put some neosporin on it, just so it doesn't get anymore infected than it already is.