Please don't use Bio Spot or any other flea products from grocery or chain stores. They are very dangerous and can kill your pet.
http://www.apnm.org/publications/res...leachemfin.pdf Bio Spot - Flea & Tick Control for Dogs - Consumer Alert
As I told you in your other thread, the Capstar just killed the adult fleas, not the eggs and larvae. When he scratches, they fall off and hatch in your carpet. You need a good topical that kills all stages of the flea from your vet like Frontline or K9 Advantix. You may have to treat your carpets or bomb your house if you can't get ahead of the fleas.