Not sure if you have a "Henry"s" store (or other health food store) where you live, but you can get homeopathic medicine and treat this. I just finished treating a button quail with the exact same issue.
There is dissolvable pellets made by "Boiron". Just crush between 2 spoons and mix with a few drops of water and feed with a dropper.
Here is what I would do:
If you feel the bird is in shock - use arnica 200ck twice a day for 3 days. If no arnica, gelcemium 30c 3x a day for 3 days.
For swelling of the head - use hypericum perforatum 30c 3x a day until better.
If you think there is neurological damage - use ignacia 30c twice a day for 3 days.
Liquid B complex from GNC helps with stress, increases blood flow, energy, appetite and encourages faster healing.
Vitamins in the water are always helpful.
Neosporin on the head to prevent infection. If there is bleeding or the wound is re-opened use corn starch or flower to promote clotting and stop bleeding. Dont pull skin off, it will take care of itself in the healing process.
You should see improvement around day 3, make sure the chick is eating and drinking.
These are some methods I use for rescue birds with head injuries.
Good luck!