Lice: ONE Found?

2 days ago, I found one single louse after braiding my daughter's hair about 3 times on the top of her head. I grabbed it, killed it, and kept it in a bag to confirm that's what it was. I've been on this crazy rampage since, researching, combing, combing, and there is absolutely no sign of anything. She has the clearest scalp, no dandruff or anything. I know about the eggs and the nits now and their characteristics and I've egg combed and subsequently nit combed her hair in tiny sections until she fell asleep on my lap. I'm not kidding- I don't want lice, but there's no way they can be that undetectable?! I will continue to comb every day and night with my special combs, but now I'm worried I have lice. She is in school, but they say there's never just one, and I don't know how I could comb myself if I can't even find them on her. We have no itching or signs at all. I literally found one and I'm freaking out- better that than an infestation. I get creepy crawlies just thinking about it. Please help me, I've watched all the youtube videos and it sure does look like if there was a case of lice going on, there would be detectable signs. Is there anything I can do to better detect it? I take the hair in super small sections and focus on the very scalp, then take the comb all the way through her long hair from the scalp. I find nothing.