Important: A concussion can change in the first several days. Even if you've been cleared by a doctor or an emergency room, symptoms could change or worsen.
If you have several concussions within a few days or a week or two, it could result in second impact syndrome (SIS), which could be fatal.
If you have any questions or are wondering if you should call a doctor or go to the emergency room, review the information from the CDC to help make that determination. If you are a teen and are wondering what to do, tell someone: a parent, caregiver, family member, friend, coach, teacher or someone else.