Red bumps on dogs groin area - help!

We noticed two little red bumps on our dog yesterday and today it seems to be blistering over. Anyone have any idea what this could be? It is on his groin area. When i touch them it doesn't seem to bother him. But we noticed him Biting at the area earlier!

Our dog is a 2.5 neutered male yellow English Labrador! We noticed two red bumps yesterday but now they are looking to blister! He seems to be acting fine otherwise. We are in the Houston Texas area.