Maderma...(sp?) is made for scarring... but I believe it is when the actual scab has formed. I use Neosporin on everything and love it.
My daughter suffered a scar across her face when she was about 4 years old, you can hardly see it now...
Kids heal very well... keep that in mind..
DONT LET HIM PICK at the scab!!! (very important)
Use Neosporin or cream like it... and it shouldnt be as bad, but that picture looks like he will end up with a mark no matter what you do.... making it heal as best as it can with out picking at it..(hard with kids) is your greatest bet.
Good luck!! It looks like it hurts..