Head lice is not the end of the world. It doesn't mean that you are not clean. I don't like bugs any more than the next person. When two of my boys got lice in middle school, I checked with the nurse at school and she told me that there was an outbreak on their bus. It would have been nice to know about it before it was out of control. My boys had hair down to their backsides when they were younger. I spent a whole weekend combing through that hair. I just used something that I picked up at the drug store with the little comb and went to work. I think I might have gone through two of those little combs that weekend. One thing I can say is that after all that attention to their heads their hair looked great!
I would suggest that if you are going into your child's school, outbreak or not, wear that long hair up and don't lean in real close to other kids when you are working with them. I remember one little girl in one of my son's classes that was a real hugger. When I went in to help the teacher, I wore my long hair up on my head. Boy am I glad that I don't have to worry about head lice anymore. Good luck.