Susan
We had an awful time with this too with both of our children, but especially with our daughter who has extremely thick, long hair. The first time it happened, I treated all 4 of us with RID- it did not work. Also tried another name brand product which did not work. After calling the "National Pediculosis" Assn, and learning what chemicals/pesticides were in the products, I stopped using any of those treatments. Our son was very tender-headed, so I finally decided to sit him in the tub & shave his head- luckily it was summertime. The most effective route for me was combing (now I know what the phrase "nit picking" really means!) her hair every single day with a lice comb- it literally took hours. She would sit on a chair on a sheet that I spread over the carpet. I sat behind her under a strong light with my comb & a bowl filled with boiling water. I would submerse the comb in the water with each stroke to capture/ kill the lice then flush it all down the toilet when done. If the nits were too close to the scalp, I would cut the strand of hair below the nit & add the whole thing to my bowl. Also vacuumed every day, washed everything she wore (as well as blankets & pillow case- would put the pillow in the dryer for 15 minutes as heat seems an effective way to kill them) & had her sleep on a cot which I would also vacuum. Blow drying the hair was recommended to me & I really think it does help- again the heat factor. Also used full-strength vinegar rinses that I let dry naturally on her scalp/ hair. Good luck to you! Hope some of this advice may help.