Milk blister???? Help!!

So I just noticed a small flesh colored blister in my nipple. Not on it, in it. It stings real bad if anything touches it and it more painful when my nipple is erect. It also seems like it's causing my nipple to constantly be stimulated and be erect. I've done some reading and found that milk blisters can happen during pregnancy, but I'm only 12 weeks! Anybody have any ideas? Or suggestions?? I emailed my doc, but I'm just wondering if anyone else has experienced this.