Good story, hit me on a personal level too as a semi-recovered anorexic. It's rough to comeback from years of verbal/psychological abuse. Good on MC for apologizing, though the apology was still kinda a wet fart due to the fact he only apologized to get with her.
Idk if I really agree with the "spilt milk" saying applying here, as usually when I hear that it's about feeling bad over something you shouldn't feel bad for in the first place, like spilling your milk is just a simple mistake. Bullying isn't really a simple mistake, you actively choose to do that.