[TKCR]

Mine was a bit messed up there in that are too. I used a little tape to just hold it all there together. But if your actually missing some fiber, you will have to fill it will some spray. They have some that has that fiber material.
Once you recover your headliner with new material, you'll never now it was there. Especially since it's up in that corner, where the visor is.

Here's a pic of another one I did for a buddy, the blue one. It was the same way. This just after getting the new headliner material on and before trimming the excess around the edge.