I just got hit in the back of the head with a hockey puck. would there be obvious symptoms of concussion?

Can be: Some of the more common symptoms include confusion, headache, nausea, vomiting, blurred vision, and loss of memory.

Concussion: Symptoms may include, but are not limited to headache, nausea, vomiting, altered level of consciousness, confusion, blurry or double vision and incoordination. I would take it easy for a few hours and see if any of those symptoms develop. They may be delayed. If any severe symptoms, loss of consciousness, or continued vomiting go to the er!