My son has it, too--and the co-morbid ADHD that (sometimes) goes with it. My son will be 11 in August. I feel your pain. When my son was in 3rd grade, he had to go to the bathroom during class one day. He raised his hand, to ask permission to go. His teacher refused to let him go because she said he "gave me a 'look' ". HE HAS FACIAL TICS !!!!!! I'd explained that to her previously (she was young, and it was her first year teaching, so I guess she didn't know anything about Tourette Syndrome), as well as I could. But--she didn't allow him to go to the bathroom, and he sat there and wet his pants in class. Then, because she wet his pants, she made him stand outside. He was so humiliated! My heart broke. I've never felt such violent anger towards anyone in my entire life as I did toward that stupid bitch of a teacher. Of course, I couldn't strangle the life out of her, and I managed to have a conference with the school's principal about the incident without yelling, cursing, and sounding hysterical. He is no longer in that school.
He's grown very brave since then. We joined the TSA (Tourette Syndrome Association), and he gets a monthly newsletter which is written by kids with TS. When he went to his new school, I explained (as I always do for his teachers) his affliction. He, with no coaching from me, took his newsletter to class for show-and-tell. He stood up there, in front of his new class (at 9 years old) and explained why he twitches, and passed his newsletter around for all his classmates to read. I was so proud of him. I still am. The kids never teased him after that. He's very happy and successful in that school.
I'd strongly recommend you look into the TSA, CaroGirl. They may be able to offer you some comfort, ideas, solutions for helping your son be as happy as possible...