It is no easy to repair scratches in Sandblasted Ti, and Sandblasted metals in general, because it is no easy to macth the finish.
You would need to make the sandblasted again.
If you can get it, this is the best and maybe only solution.
Try read this link, maybe you have some clues about that, but I think that it will work for brushed surfaces not for sanblasted ones:
http://www.paneristi.com/archives/polishing
Perhaps you can have results rotating the Ink Eraser (??)
ALE
Maybe that could be a solution with rubber bezel
http://forum.replica-watch.info/vb/showthread.php/chronopassion-rubberclad-project-107724
ALE