With my first child, I had and survived mastitis and clogged ducts. I've got my first painful episode with my second child as I'm trying to adapt from 5 pumps a day down to 4. I'm pumping, bathing, massaging, warm compressing, etc and still feeling some pain. Now I notice a white pocket on to the tip of my nipple that is 3-4mm in size. I noticed it yesterday and it grew a tiny bit today. It isn't dried up milk that I can brush away. It's under the surface. Do I need to worry or do anything about it? What is that?