Something that always bothered me when Yoshiki learns from Asako that Hikaru half-deafened her and questions him about it (and later when Asako confronts Hikaru and he tells her what he is and did) <-actual spoilers is that Yoshiki doesn't interrogate why Hikaru can't go back in and undue what he did in a kind spiritual surgery. It's confirmed by real doctors that there's nothing physiologically wrong with her, so Hikaru ought to be able to mend whatever he ripped up inside her (not saying that the recovery process might not be long/hard but at least it would some measure of atonement).