Just out of interest, now that you have your mark sheet - was it just one section that was dreadful, or did you miss pretty much every section by a mark or so?
I'm an instrumental teacher and have never asked for a re-mark or heard of anyone else doing so, but if your teacher is thinking of doing it anyway then you may as well go along with it. Bear in mind there may be a fee for it though, so you might be better off just doing again and preparing more thoroughly than last time.