My guess (that's all it is) is that you're using a flange that's too big. If it wasn't doing that before and you know it was too small before. It's perfectly fine to give milk that has a little blood in it, so don't worry about that. But if it's making it worse, I wouldn't use that flange again to pump. Can you use the old one? Or pump one side with the 27mm and then pump the larger side with the same one?
Is there an open wound on your breast? Or is the blood coming out of your breast and there is a hickey underneath?
“We are not put on earth for ourselves, but are placed here for each other. If you are there always for others, then in time of need, someone will be there for you.”