The phantom pain. Only so much regret you fits in the human brain. Losing a piece of yourself is harder than people realize. Far harder than she was thinking when she got tricked into mutilation as basically still just a kid.
Imagine if you were a brilliant painter. Able to create images with physical arts that made people marvel, you weren't just a good painter, you were a prodigy, exceptional, a virtuoso. No one else was as good as you at a young age with your innate ability when they had tried their whole lives.
Imagine that whispers from those other people started creeping into the corners of your life, saying, "People only like you because of your painting." "Aren't you tired of just being 'the painter'?" "People only ever want to talk about your paintings, not you." And you're young, and you begin to agree with them that you are more than just a painter, and the world that knows you for your painting should know you for your personality, even though it's not your personality that is exceptional. They begin to say, "Maybe you should just get rid of your ability to paint..."
You decide to take a lawnmower and stick your hands in to mangle them forever, so you'll never paint again. Everyone around you applauds you for being sostrong and brave as to reject society's pigeonholing you. It's so wonderful what you've done and for a while you get attention for it. then the attention fades, and you've got nothing to do with your time. And then you realize that you really loved painting. You try to paint again but can barely produce smudges on the canvas. You bring these smudges to others and they humour your effort, but you can tell it's only faking. And then you truly realize the gravity of the irreversible action you've taken. You eliminated not only the thing that others loved about you, but the thing that you loved about yourself, and no matter what you do you cannot reattain it. Ever. Imagine having to deal with that feeling of loss, every day.