Err... I hate throwing the left hook with the back of the hand facing the ceiling. I'm betting you that's what hurt your wrist.
Try taping up your wrist, or wrapping it, when you're not at the gym. Just when you're around the house, and when you're sleeping. Keep it as stiff as possible. If I ever hurt my wrist, I use this trick, and within 2 days it usually feels 100% better.
If I were you, though, I'd get that topical cream.