You can file a brain injury claim any time someone elses negligence causes you to sustain serious injuries, including cases in which you may have chosen not to wear a helmet at the time of the incident.
Talk to an experienced brain injury lawyer at Morris Law Firm to better understand how much compensation you have the right to pursue, including what evidence you may need to show to establish the other partys liability.
Note that South Carolina does not require helmet use for motorcycle riders over 21. However, failure to wear a helmet substantially increases the risk of collision-related brain injury, neck injury, or facial injury.