Is it really that bad to tell a girl she looks tired?

[Joe]

There's this beautiful girl I work with (I'm a guy and I work at American Eagle) and I kind of have a little bit of a crush on her. Today at work I said "Hey, what's up" to her and that she looked tired. And I didn't mean that she looked tired in a bad way though, she actually looked absolutely beautiful today. So I was on her twitter and saw she tweeted basically saying, "There's nothing worse than someone telling you that you look tired.. Thanks I know I look ugly today" and now I feel really stupid. I feel like I just lost any chance I had with getting with her. And also, I don't have her number or hang out with her outside of work, I just work with her.
So now I don't know what to do because it obviously looks like that was definitely the wrong thing to say, even though I didn't mean it in the way she took it. But I also don't want to let her know that I didn't mean it that way, because I don't follow her on twitter, so she would think I'm a creeper.