-It has to leave permanent damage that would make the victim horribly bitter about the whole incident
-It has to leave the victim able to fight, though not necessarily at the beginning and not necessarily well.
-It has to be doable in a medieval fantasy (think D&D) setting.
-It should be traumatic and very creative (no just chopping off an arm)
-It should not damage her internal organs, so no gas that burns her lungs or whatever.
-I'd prefer it not to involve neural things, considering her mind is already weird enough.
Any ideas? I've thought of simply messing up her face real bad, but yeah. The victim is female, if you wanted to know, and the perpetrator is also female.