How Can Head Lice Causing Scalp Damage Be Treated?

Hi my daughter has had headlice now for over a month i have tried 3 of the solutions over the counter, hedrin and 2 others im not sure what they were called. I do her hair with conditioner and combing nearly every night but they still don't seem to be going any where. Do you have any other suggestions? thay are damaging here scalp because she is scratching that much. Thank you