Its hard to deal with episodes when we find ourselves saying something or sounding like someone who abused us; especially when an abuser was a parent and we want to be as far away and different from that behavior as possible. To not repeat anything that even remotely resembles that behavior seems to be as much of a need as breathing, but the problem is we are human and things happen.
Remember that you did the right thing by apologizing, and also you probably see it as something far worse than your daughter does. Children can push buttons like no other and it is NORMAL for a parent to sometimes overreact. It doesn't mean that you are a bad parent or a bad person, it was just a bad incident. Give yourself permission to be human and forgive yourself.
I did keep all scissors, knives and other sharp objects in a childproof drawer, but I had four children and was definitely outnumbered. :D Don't get me started on Sharpie markers as those went immediately into the trash if I found them in the house.
I loved Scared of Lonely's hat suggestion. Also, the "do it yourself" haircuts are funny a few years down the road, especially when your teenager is trying to rationalize why they NEED to spend more than $100 at the salon.