Internal head injury
does not always associated with any external injury.
Compare this pain with the previous pain of migraine
in term of character,site, duration,severity of headache and associated symptoms.
As you are suspecting this pain is due to migraine, you must have given the medicine for that. See the response to the medicine.
Consult your doctor for clinical evaluation for any signs suggestive of injury to the brain. A neuroimaging
may be needed.