Thanks for using the forum. I am happy to address your questions, and my answer will be based on the information you provided here. Please make sure you recognize that this forum is for educational purposes only, and it does not substitute for a formal office visit with your doctor.
Tourette's syndrome is defined by the presence of motor and vocal tics occurring over a specific time period. Not everyone with tics has Tourette's, there are specific diagnostic criteria that must be met.
Tourette's syndrome can be primary, meaning not secondary to anything in particular, or it can be Tourettism, secondary, meaning it is secondary to something else such as infection, trauma etc. To my knowledge Tourette's does not result in brain damage or changes in brain activity per se but rather results from dysfunction in specific pathways. In someone with pre-existing Tourette's, the added stress of head trauma can certainly make tics more severe, though in some cases this is temporary, only during the initial stages of the head trauma.
Tourette's does result from some sort of dysfunction in brain activity, in part in the pathways of one chemical in the brain called dopamine. Tourette's syndrome may be associated with other problems such as attention deficit disorder and psychiatric problems. Tourette's may get worse during periods of stress, anxiety, it varies with seasons, and with co-morbid psychiatric problems.
Thank you for using the forum I hope you find this information useful good luck