I feel terrible about my baby, what should i do!?

I was making a bottle for my daughter and half of it spilled, so I went to get a paper towel. I was holding her on my hip and I couldn't get a sheet to rip off since I only had one hand free, so I yanked it hard. As it ripped my hand flew back and hit my daughter on her forehead. I feel so bad! She cried immediately, but she only cried for maybe a minute. I feel like the worst mother ever! There is a very slight red mark, and you can only see it in my fluorescent lights if you try to look for it. There's no welt or bruise, but I am so worried. What should I do? Please don't make me feel worse than I already do.