No; Licefreee Spray starts killing lice and nits that come into full contact with the product when it is applied to the hair and scalp. After the hair has dried (naturally), the treatment is complete. The 7-10 day window is a recommended time frame to perform daily head checks in case a louse or egg is missed during the treatment and causes a reinfestation. If during a head check, a live bug or new nits appear, it is recommended to perform a second treatment.