What things should be avoid having a concussion?

Head injury: Maybe I am missing something here. Nut the only answer to this question is to avoid a head injury!

After a concussion..: Things that you should avoid after a concussion include strenuous activities or activities where you will have excessive physical and mental stress. Activities which exacerbate the symptoms of concussion (ie. Headache, blurred or double vision, nausea) should be avoided. Alcohol should be avoided. Finally avoid activities where you can sustain another head injury and concussion.