I think you might be overthinking things. Hurt feelings aren't the end of the world.

You gave him all the information he needs to understand the situation & feel better, which is that you were just kidding and you are sorry.

It is now up to him to handle his emotions.

It's not your job to make him feel better - it's also not possible - that's something only he can do. It might take him a little time, and you should respect his need for time, but he'll be okay.

Let me know if there's anything you want me to explain more clearly, I'm glad to do it!