Did she say she can't see her body at all, or that she can't see her reflection? Because I thought it was the latter. I wonder how difficult it would be to not be able to see your own arms/legs when trying to move around or interact with things around you. You could try to simulate that with VR, but it's not exact since you wouldn't be able to feel your surroundings.
Maybe it will be introduced in the story as the solution for Amber's problem, just like how Moonsong came up with the pills that the MC can use to capture powers.