If it scalped the skin it may never grow back, but it doesn't look that bad - I'd say it start growing back soon but won't look anything close to 'normal' for quite a few months.
Antibiotic ointment - thin. You should probably keep him seperated for a few days until it scabs up, you can put him in the crate in the pen with his ladies during the day, but wouldn't let him loose with them because they will want to peck his head while its freshly wounded/ You can try blue kote on a cotton swab or piece of cloth (would definitely wear gloves) and dab it on his wounded areas, should help keep it to one area and out of his eyes.
Also agree on supplementing him with eggs, electrolytes in water (or even just sugar) for a couple days - keep him boosted to speed up healing and get over the stress of the attack.
I just kept applying the triple antibiotic every day and syringed her when she refused to eat.
