Looks like what's missing is some fairing putty.
If it was mine I would fiar it back in with thickened epoxy, or you could just fill the hole with some, or caulk it with 4200 or 5200 etc.
Looks like polyester resin and cabosil to me. We used to bed them in thiokol which is like a two part 5200. You may want to have some small wedges to hold it in position until everything sets then finish tightening up the fasteners