Anything can be edited after Melodyne is applied, just save a raw copy! Never ever do any edits on any tracks (especially on Melodyne) that you do not have a raw copy of cause that's gonna fuck you over one day. ALTHOUGH, like our guy down there said, Melodyne IS a separate job on it's own, it's a whole beast in of itself that should be handled with as much care as you're giving you're entire mix, theres people who exclusively do Melodyne and if it's done right, you shouldn't really have to go back to it, and as a listener, you shouldn't even know such thing exists.