how should i start talking to him about this on facebook?

[Betty]

Earlier today, I started talking to him. It was real quick, I kinda asked him a question, but he kinda laughed a little and shook his head, and said he had to go. ....I kinda wanna just say something on facebook. I have never chatted on fb with him before. I was thinking I could asking him, something like-- soo, you never really finished up answering my question earlier. But, I am not sure if that sounds stupid. What do you think? Is there a different way to come about saying that? Or should I just try to say something else?