Thanks for posting,
In my humble opinion I do not think you should be worried much about the situation (i.e if your fear is progressive intracranial injury
). From your description it seems to me that the shock has only provoked the already existing headache and all you need is some analgesia. OTC NSAID will do the job. Nausea
is probably related to the headache.
If after taking the NSAID you still have the same problems, please consider visiting a neurologist
for more effective medications. He might request an MRI or CT scan
Hope this helps