Depends on how big the hole happens to be. If its not too big you could use a ceiling medallion. They can be as plain or fancy as you like. Most can be painted. Some like at Home Depot are under $20.
Medallions come in all sizes and will cover the hole nicely. Just paint it to match your ceiling color.
I'm agreeing with the others. We replaced an old ceiling light with a fan/light combo and used a medallion to cover the larger hole. It actually adds to the appearance of the ceiling. Wishing you the best.