We have 3 scenarios....
1) Pakhi will survive by some miracle and come back twice as evil than before to take revenge from Virat for not saving her and choosing Sai - perhaps she will come back as a supernatural being like a naagin or a vampire and torture Sai. (I would have said with a plastic surgery so no one recognises her, but since this is Aishwarya we are talking about, neither Venku nor Neil will get rid of her)
2) Pakhi will will die and be reborn, to make way for reincarnation track.
3) Pakhi will die and not come back. Perhaps generation leap and Aishwarya will come back as new FL with Ayesha or a new actress as the vamp.
If second scenario happens, and Virat will also die and take rebirth, that will make Pakhi older than Virat so I doubt it will happen. But you never know.😆