If someone gets hit on the head but not knocked out, should i try to keep them awake? how long?

No: If this is a concussion, then close monitoring of the patient is important, but does not include keeping them awake. Look for major behavioral changes, balance problems, vomiting, slurred speech, major memory loss, weakness on both or one side of the body. If the patient has a severe headache, then these are reasons to seek immediate medical attention. Also, there is no need to wake up someone.

Depends on symptoms : This depends on what your symptoms are there may be no need to keep him awake at all. If you're getting now Mr. tingling vision problems yes. But it has to be done in an appropriate fashion. You can discuss it with your physician

Head trauma: Observe if someone hits their head, no loss of consciousness or change in mentation, no worries. Ok to observe with person awake and sleep as needed. If change in mental condition occurs, seek help in emergency room, change in vision, balance or HAs prolonged.

Closed head trauma: Initially i would try to keep them awake for 2-3 hours and then check that they are arouse able every 2-3 hours for 24 hours. If there is vomiting x 2 bleeding from ears , or nose, or when you bend the head forward dripping from nose , as well as pain on the cervical spine would go to ER immediately.

As long as: possible- may be a concussion or TBI- get immediate medical attention at ER.