Dear Jwalton, hello
Thanks for writing your query.
is due to some biochemical changes in the brain due to the impact of the head injury
Usually it takes few days to weeks for proper healing. But you should take proper rest during this period. Avoid watching television and text messaging during this period in addition to the physical rest.
If you have not got a scan of your head done, get it done and consult a Neurophysican.
I hope this is of help to you.
Thanks and take care.