I just saw a white bump on my left nipple and it really hurts. How do I continue breastfeeding or pumping?

It could be a milk blister. Apply moist heat to the white spot to soften the blister before latching or pumping. If the blister does not open up, you can try to loosen the skin or use a sterilised, clean needle to pop the blister. Do not use your fingernail to dig into the blister as it may cause infection when germs from your fingernails enter the open wound. After that, nurse or pump to empty your breast and treat the burst blister with a saline solution. http://kellymom.com/bf/concerns/mother/nipplebleb/

Sounds like a milk blister! Before you nurse, try to hand express back behind and down toward the nipple to release any thickened milk that has backed up in the duct. Sometimes clumps or strings of hardened milk (often of a toothpaste consistency) can be expressed from this duct. Alternatively, you can consider using a nipple shield during feedings. Here's an article about milk ducts: http://kellymom.com/bf/concerns/mother/nipplebleb/

thanks