Not so much grown back as they were replaced with the ones she has now. Magically graphed onto her and slowly becoming a part of her. (Since metal and gems aren't quite the organic type of wings)

It won't take the wings off, just hurt her and give that fear even more then she already has about it. Also- It's part of the Scarlet's head canoned past that when she ran into hunters that captured her, they took them off