She is already back per-se, in Lin's room, has been for over a month (in-game), but she is no longer interact-able with except for "how are you" and she can no longer be summoned to the dungeon. Yes she still "exists" but we are "locked out" from any physical interaction with her. Thus my question to the creator, why add her appreciable talents to the harem only to then take her away? In other words, why turn an excellent fun sexual partner into a glorified mannequin?
As should be clear, Harem Hotel is still in development. Every character will get content eventually.
It should also be clear in game that her mind was forcefully altered and she was loaded with drugs that changed her body in ways she did not want. It is the main character's goal to heal her, and get her off those drugs.