I was playing the halo 2 anniversary campaign with my friend but got disconnected. When I tried to start up the game is said that 1 skull was on but none were selected. I then noticed that my bandana skull had disappeared. I preordered the game so I’m suppose to have the skull. I tried re-downloading the skull but it is still not there but is still turned on. Please help so I can get the achievements for completing the missions.
My skull never unlocked at all 
Mine vanished too. About right around the same time that they just released the patch (that broke multiplier even worse, to the point that it no longer works for me)
Well that is unfortunate.
Looks like you would have had to pre-order from gamestop or eb in order to unlock the bandanna skull. will be available 12/12 for everyone. see link for details.