Barbara
When my daughter had lice several years ago, the over the counter products were useless. A professional "nit picker" ( yes you can hire one) suggested the following and it worked great. Rub olive oil into hair very generously. Use a shower cap and clip tightly on head. Child must sleep overnight in this. Use Dawn dish detergent in morning to wash hair. The lice will be dead and slide right off hair. The oil and the tight shower cap kill the lice by not allowing them to breathe.