I've had 5 documented concussions in the past 12 years (lord knows how many undocumented), Im fine, and your not going to be some twisted vegetable if you get another. But i would suggest that you buy a helmet. I've never gotten a concussion while snowboarding, mostly playing football. If you love it dont quit, its a risk you take every time you strap up. When i put my football helmet on i dont think twice about it. I think you should rethink selling the gear, just get up on the hill next season and ride, chances are you'll feel a lack of confidence, but it comes back fast! Keep on riding!
It comes and it goes. Get it while it Lasts.