Is aleve (naproxen) okay to take with a slight concussion?

Yes: Most important is to rest your brain. Rest, peace and quiet and lack of stimulation especially loud noise and computer games.

No, not early on: It is typically not recommended to take nsaids, of which aleve is one, in the early stages of concussion. This is because of the small but significant risk of bleeding that occurs with NSAID use and the possibility that there may be more of an injury to the brain (a bleed from a vessel injury) than just concussion. Tylenol (acetaminophen) is preferred as it is not an nsaid.