Scalp wounds look ghastly, but most healthy birds survive the experience. I have seen birds scalp themselves to the skull and heal ok. The main thing is to keep the wound clean. Simply washing the wound with sterile water will help. Saline water is best, but boiled and cooled bottled water will work in a pinch (but straight water will burn a bit.) Make sure to wrap a towel around his body, do you don't soak him and cause him to get chilled.
I always clip wings of any quail with head wounds. This keeps them from injuring themselves while healing.
Antibiotic ointment works well, but be careful, since it can trap dirt inside the wound.
Keep him on paper towels and change whenever dirty(sometimes 3 or 4 times a day). Once his scalp scabs over, you can clean the cage less often, but at least in the morning and night.
Other than that, the best thing to do is leave him alone as much as possible. Handling sick and injured birds causes them too much stress.
The hardest part will be waiting until he is fully healed before returning him to his flock. If there are any scabs at all,the others will peck him bloody again.