I think I knocked myself out for a few seconds and I was pretty dazed for a few minutes. I had headaches for the next 24 hours, so I probably ended up with a mild concussion.
So, what did that lesson teach me? Well, I've worn a helmet ever since.
I've said it once and I'll say it again: After 17 years of snowboarding, and about 5 skiing before that, I had a collision with my buddy that left me unable to formulate complete sentences for 3 weeks. I'm not trying to start a debate, cause I know the anti-helmet numb nuts are out there, but WEAR A FUCKING HELMET FOR FUCK'S SAKE!