I had blisters during the first week and the lactation nurses guided for proper latching. Seems like the blisters happens when baby suckle the tip and also breast fed longer than the usual 10 to 20 minutes. I heard using nipple cream helps but I just applied my own milk on the area and used a cold compress. When will your next consult at the hospital/clinic be? You can get their advice too
Perhaps it is how you pump or baby's latching technic. Have you been using nipple cream after every pump and latching? If youve not, please do use it.