How To Cure Tiny White Bumps On Top Side Of Nipples?

I am a nursing mom and I have been having a problem recently. I have 50 or so tiny white bumps on the topsides of my nipples. They are ONLY on the tops. Not the tips, sides or bottom. These bumps seem to be full of a tiny bit of puss and the rest is clear liquid. When my baby nurses, the bumps burst and then the skin around them tears. The skin also has a slight bluish cast to it for about 10 minutes after nursing. It's extremely painful and it's making nursing my baby nearly impossible. Can you tell me what this is and how to fix it?