First - DO NOT use the shampoo more than recommended. It is an intense neurotoxin that DOES affect your child's brain. My sister now has brain damage and seizures due to a six month bout of lice (courtesy of summer camp) that saw my mother shampooing her repeatedly nearly every week.
My Advice: Shave his head bald. completely. and keep it that way for several weeks. Check your family. And check out Fairy Tales Hair Care at fairytaleshaircare.com. My son got lice every year from daycare til we couldn't get rid of it until we got this stuff. and he's never had it since.
You HAVE to wash EVERYTHING. His coat, his hat, his pillows, sheets, towels, clothes, anything that might have touched these things...clothes in the closet, backpacks, spray down ur furniture, cars, vacuum every couple of hours, dry clean what you cant wash and bag up in trash bags for a MONTH what you can't dry clean. This has to be done EVERY day for at least two weeks. EVERY member of your family should also be checked, twice a day, for at least two weeks. If you see a single louse or nit you have to repeat the entire process for the coming two weeks.
Get a nit comb. one should have come with the kit you bought. You HAVE to comb his hair out twice a day. it's tedious and takes forever.
Do your research on the consequences of introducing lice killer into your home and the drugstore shampoos.
Does it work? Sometimes. Sometimes not. Depends on if your brand of lice is immune to the neurotoxins or not. Some have built up immunity.
Sheets have to be changed and washed every day. towels too. all laundry has to be done every day. in HOT (preferably 150 degrees or over) or they don't die.
keep hair spray and alot of product in your hair. they don't like dirty hair. try to go several days without washing your hair.
GOOD LUCK!!! I AM SO SORRY!!!!! Lice is exhausting for Moms.