The best way to ensure you're getting rid of them is to comb through her hair with cream conditioner and a nit comb every night for over a week. If it is such a problem at the school, then I would suggest doing this once a week (regardless of the status of her head) as it will break the gestational period of the eggs, as well as getting rid of any live lice that are running around. My SIL had this problem at her DD's school, and she now does this once a week for both of them and they have been lice-free all year .

The lice treatments are all well and good, but they don't kill the eggs, you really need to be combing to fully break the cycle. I know it is the biggest PITA, but it's the only way to do it