How long do post concessional headaches last?

Post concussive . After a concussion it is not unusual to have some persistent headache, dizziness, vertigo or general malaise. So long as the symptoms are getting better slowly, I wouldn't worry too much. If increased activity worsens the symptoms, slow down and see if doing a little less helps improve your symptoms. It may take 4-6 weeks to get back to normal. If you are getting worse, go see your doctor!!
Up to 3 months. post concussion syndrome usually start within one week after the concussion and can last up to 3 months though they can persist for over a year.