Head hit into another persons head on eyebrow bone 4 days ago. dr said exam ok, just sore/headache- only symptoms. when should mild headache subside?

Headache: This mild headache could continue for a week or even longer but should gradually improve and not worsen. OTC Tylenol (acetaminophen) or Alleve can be helpful.

Concussion: Well, a mild concussion (as yours sounds to be) can take a week or more for all of the symptoms to subside. It can last much less, or a little after, but most of my patients have resolution by a week. Just remember to have some brain rest, and no vigorous exercise for a few days, and you should be fine. Good luck!