Make no mistake-this is not your mother's beauty book. Every teen knows it's all about hair. If your hair looks great, so do you. And what's more, you feel great. A bad hair day might make you want to pull a blanket over your head and stay in bed. Don't do it. Don't waste a minute of your life feeling insecure and un-pretty. Wanting cool hair doesn't mean you're shallow: it means you know the ripple effect of great hair. You feel smarter, funnier,...