I Spilled Coffee All Over My Boss's Report

So this week has been one long drag at work. I've been trying my best to stay focused and not let the monotony get me down, but honestly, it was too much for me today. I had a meeting with our client in an hour, and I needed to hand over some reports that I was working on for weeks now. They're so important, everyone has high hopes for them. But as I was rushing around the office looking for my notes, I accidentally knocked over a coffee mug onto one of those critical reports. It went from black ink to brown mush in seconds! To make it worse, I spilled it all right on top of my boss's name and title at the top of the page. Now she’s going to think that either I'm really careless or that I wanted her to fail this project somehow. Oh no, what am I supposed to tell her?!