I saved the town and tiris's mother came after me for help. I talked to him and went to find the creature(which is riejik hidesman) and the guy in the south helped me. When i got there i think the man he told me to kill wasn't riejik but the girl or something. Now with the Tiris's girl back the parents said she wasn't herself and they went out on a walk(the girl is prob. Riejik in disquise again). But now i cant find any of them and the quest doesn't have any more entries in my journal. Please tell me where to Riejik.

You needed to cast restoration on her before she left... can you reload and do it again?

Other than that, are they at the house?

you dont kill the person laying on the ground you kill the 2 telling you to kill the guy on the ground. then once you kill them the girl gets up off the ground gets back into her own skin that one of the other 2 left. you then cast a lesser restore or greater or even heal if you got a high level cleric. quest almost done , go back to the house talk to the rents and youll get +1 reputation

yeah, if Reijek is in disguise as Raissa, then Tiris gets taken away (and likely killed) and his parents feel weird about the "new" Raissa. it sounds like a weird bug if she went home without you curing her. i would reload.