I suggest you save your money on stuff that literally has zero effect on lice. Also that stuff you washed her hair in is nothing more than pesticide. So stop.
Go to headlice.org and follow their advice. Run the sweeper on all fabric surfaces. Wash the bedding and dry it.
This is how I get rid of head lice and maintain it.
I wash te girls hair, it's nearly waist length and pretty thick.
I condition it then comb it out. Rinse out the conditioner but don't towel dry it.
I sit her down in front of me and I use a rat tail comb to part her hair off.
I use a magnifying head gear that I got at Hobby Lobby. I use a good lamp.
As I part her hair I do a section of about 1/4" - 1/2" of hair maybe 3"-4" long. Then I comb it all the way to the end while examining the hair with the magnifying glasses on my head. I can see if there are any nits on the hair shaft because wet hair lets them show up better.
Then I examine the hair close to the scalp. I look to see if there are any live bugs. They are stunned from washing the hair and as long as the hair is pretty wet they don't move very fast. They breathe oxygen just like we do. So being doused in water traumatizes them.
If I see a live bug I pinch out or use tweezers. I drop it into a glass or cup of water. It drowns quickly. If I see white nits I don't worry, they are hatched eggs. They pose no harm at all. If I see a nit with a dark center then I either pull that single hair out, snip that single hair with a tiny pair of scissors from my manicure set, or I use my nails and slide the dark nit down the hair shaft then drop it in the cup of water too.
If you do this every other day as long as you find any eggs or live ones you are maintaining the outbreak. If you are finding a lot of new ones then you need to do this every day.
Once you have all the little critters gone do this every week. We do this every Saturday morning. It's just our routine for my granddaughter to get up and go take a long hot shower. She will come out when all the hot water is gone.
I am so used to doing this that I can do her entire head in about 5-7 minutes. I am used to seeing the difference where a bug is and where a nit is. It takes practice and knowing what you're doing.
I swear that the magnifying head gear is my secret weapon! I can see her individual hair shafts and can see even the smallest baby on her scalp.
I have, even after all that I do, had to treat her once. She was going to a friends house that had lice every time. I used Lice MD on her head and it was the best thing ever. It's not a pesticide and it did the job where most everything else doesn't do anything.
So if you have done everything and you still have them try the lice MD.
BUT 99% of the time simply not using that waste of money called lice treatments and special products to get rid of them will get rid of them anyway.
Those products say they get rid of the lice but I truly believe it is the combing and working through the hair, pulling off bugs and nits that actually get rid of them.