I'm not really sure what it is... I have about five blister/pimple looking bumps all in the same spot at the base of my nipple and it hurts so bad when he nurses on that side. I'll get a pimple like thing every once in a while but it's usually just one and goes away in about 2-3 days. I've had this for about four days now and it's gradually become worse. Could it be from his top tooth that's coming in? It's only on one side though... humm... Thanks for any suggestions!