I've personally not heard of Cymbalta used to treat tics but then again I'm not up with it all like I used to be, but I figure if other things are being helped by the use of this medication then that will help calm your tics. I just read some articles about it being used for chronic pain which was interesting.
Whatever you do, don't go cold turkey on the Cymbalta if you decide you want to stop it in the future.
P.S. I hope the Neuro you're seeing is one you know already or at least if a new one is someone who has very good knowledge of Tourette's Syndrome. If you're concerned that they don't, then I know someone who I am sure would be able to suggest alternatives.