I mean it makes sense... but is there a way to go back? Before entering i had her turn me and after leaving ive tried becoming a werewolf and curing myself... both prevent me from re-entering. So i guess i have to start all over from before i entered then...

pls respond

go to serena and she will make a vampire again.

at any time? I tried to see if it was a speech option but it wasnt.

Yep,should be at anytime. you could try to make her your companion and maybe then she will.

Doesnt work... Did you beat the whole questline? I didn't

It seems going for the soul trapping is the wiser choice.