Hello Welcome to HCM She suffered bad car accident and concussion in head. She has amnesia or loss of memory to the events. She also have complaints of headache and pain in eyes. Such types of symptoms are common complications after head trauma. Difficulty in concentrating is also due to post trauma sequel. Smoking marijuana or cannabis will not benefit her instead this may prove deleterious. Seizures can be precipitated. If problem persist and she don t get relief with OTC analgesics then consult a neuropsychiatrist for management. Get her CT done to ascertain if there is any hematoma. Drugs like Sodium Valproate are commonly used in headache associated with head trauma. The drug also result in protection from post head injury seizures. Thanks, hope this helps you