Get a right size for flange. Stick to one. If not, nip will be painful n can’t pump well. I had that back then while bf my lo. I kept applying Nipple cream n let it cool down for 2 days. And feed fm. But I managed to pump (lower suction) next day. Hurt a little but still ok. Maybe you can try lower suction n pump lesser. See if it’s ok. If u have ebm in freezer/fridge can let baby drink while let your nip rest too. If Not can consider fm for 1-2 days.
Ugh i feel you. I lowered down the suction to my comfort if it gets too painful for a few pumping sessions.
Lower suction power, or if want to give nipples a break to recover, can hand express for the time being