I'm dying to be you

Y/n is a quite and collected girl who doesn't really say much or opens up herself to family Until one day she fell ill. Her grandma desperate to help took her to an old spices shop. The woman recommended her own herbal remedy which y/n took. Apon drinking it she felt better. But soon she realised if she ever sneezed or coughed she'd turn into a mass murder.Her mentality would just snap and she won't be her usual self.

If she doesn't drink that remedy she would become ill again and stay in her murderous mindset forever.but there's one problem the one who gave her the medicine. Died. And she doesn't know how To make the medicine,Her life depends on it. What will she do to resolve this?