Sent a stupid text message.. how to make it better?

Play it cool. Send another text and tell him you were talking to somebody while texting and they word 'lady' was used and you realized you then used it in your text. Just laugh about it. It's not a big deal. I'd probably text the girl back and give her ****, knowing she was joking. Maybe he hasn't read your text yet, so he hasn't messaged you back. But like I said, just play it cool and laugh about it.