Hi, I'm not a usual poster but I’ve noticed your predicament. I am an axolotl owner and have experience working with numerous animals (including amphibians) at my job at the National Zoo. I hope I can help you with your problem.
I'm surprised that you put him in the fridge since he just fell out of the tank. Usually a change in water temperature often adds to the stress. I'd say it would have probably been best if you just returned the little guy back to the tank the moment you noticed him out, seeing how there were no injuries or infections. Give him some alone time and privacy and you'll probably find he'll be back to his old listless self in no time.
P.S- If this post has copied over sorry about that.
(Message approved by jennewt)