What's the treatment for a concussion?

Rest. Rest and avoid nsaids. Refrain from any activity where you risk a second head injury while still recovering from the first. See your doc and if symptoms last longer than a week, or worsen at any point, you should be re evaluated.
Time and rest. There is no specific treatment for a concussion other than time, rest and close observation. A key in athletics is disallowing a return to play until all symptoms, both at rest and with exertion, have completely resolved. Medications and supplements are occasionally prescribed to treat post-concussion syndrome, but these should be carefully discussed with a physician who specializes in concussions.