Mm... But if it can change, it'll be harder to keep track of everything. Just because someone is blind today doesn't mean they will be on Thursday night, or on Saturday. That would make it harder to figure out what's happened.

[ at least thinking this out is helping her calm down a little? ]

...And if someone regained their sense of touch after killing someone, they'd have a better chance at hiding any wounds they picked up, or at least explaining them away.