what happens if you become a vampire during chasing echoes in the dawnguard faction?

Answer 1

not sure in the long run but right now the dawnguard keep saying you're cursed and then they ignore me after telling me to cure myself. However in the TES wiki they say all the way at the end Serana will again offer up the vampire lord ability so I say, take vampireism, cure it, then take it again after you finish all the quests. Save just in case she only gives it once