The timing of lice treatment all depends on what happens after the first round of treatment. Typically, you will begin seeing results within hours. It’s best to do a second treatment anywhere from seven to 10 days after the first round. However, if you still see live, active lice around eight to 12 hours after treatment, it’s possible the treatment did not work. Contact your child’s health care provider if you see no difference after the first round of lice treatment.