GOSH! I am so stupid! Now I remember, to heal her u need elf liquid gained from Aoi or the her mum Junsa Sakurai
I dont know if u gained it right away but how I got it was Banishing the ghost in university, and on the upper floor somewhere there should be a quest (go through all the rooms) I know that somewhere girl falls from a ceiling and asks you to come with her to the bathroom. She asks if u could make her a baby, but someone stops you and tells you to make elf liquid a give it to her first. Just make 3 flasks of it and u are good to go. Also U can use the elf liquid to heal yourself.
Imma update my misguided guide!