Fingers
I know magicians are very limited in what they can and cannot heal, but I cant remember if they mentioned whether or not they can heal severed or amputated fingers. I mean it seems kinda silly that they couldn't considering the source of literally all of their magic comes from their fingers. Marina lost fingers when they were bitten off, Dean Fogg lost his hands when they were crippled by the beast, and then the beast was helpless against Alice when he lost use of his entire left arm.
If Marina had lived, could she have recovered her fingers, or would she have spent the rest of her life only being able to do one-handed spells?