So in the vamp quests where you must infect people with vampirisim I got a quest to infect someone I've already infected and I cant feed on them again with vampire's seduction so does anyone know how to fix this?

Any time I get one I've already done I reload a save from before I talked to him like when I entered the castle and go talk to him again and again till he gives me someone different

ok was kinda hoping there was a better way but oh well.

You have to kill her to fail the quest sadly. I had this problem and disregarded it. Maxed out vampirism and didn't wanna reload that far back.