If he runs a fever or the scratch is bright red AND looks inflamed (swollen) or you see any yellow, green or even white around or in the scratch it could be pus forming so you would then need have him seen by a doctor.
Wash it with soap and water, dry it and put "New-Skin Liquid Bandage" on it, you don't put Neosporin on, it's not needed. It's a liquid you brush on, it dries, and protects the wound so it can heal, hospitals apply it over stitches. Their website says "dries rapidly to form a tough protective cover that is antiseptic, flexible, waterproof, and lets your skin breathe. Just brush on New-Skin® Liquid Bandage - One stroke protects the wound by keeping out dirt and germs and provides protections against infection with an antiseptic." Our pediatrician recommended this when my now 2.5 y/o wouldn't keep Band-aids on his forehead when he had stitches last year bec he kept trying to pick at them. You can purchase it at Walgreen's, Walmart, Target, CVS, etc., for about $4 - $5. (And, if you find another brand it should be comparable and do the job as well.)
http://www.newskinproducts.com/en/Products.aspx