You should first ensure everyone involved receives medical treatment. When involved in an auto accident, the body is flooded with adrenaline, although you may think you are fine, potentially weeks later, you could develop symptoms. If you're able at the scene, obtain witness contact information, and take photographs of the scene. If the accident was not your fault, contact your insurance company and provide details of the accident. Record every detail about the accident, then contact a rear-end accident attorney.