If the glass is not worn through, you could just put a coat of epoxy on it. If you wet the area with water you will see if its going to wet out clear. If you get some white areas, just wet sand with some fine grit like 400 or so. you see it wet out with the wet sanding. Normally adding glass is only necessary if the glass is totally gone or you need a structural repair.
You could put glass on it but I wouldn't. Then you have to feather the edge and full the weave etc.