Knots in hair and headdlice?

Okay well i have layers, and i always get head lice !! Know any good tips on getting rid of headlice? I have dark brown hair, and it gets thick really easily, i brush my hair everyday, i always have my hair down, but, under my hair, like the lower layer it always gets knotty , like really easily it took me 2 hours the other night to brush it all out! my hair is about shoulder length,...