Don't panic and do anything drastic like re-pot it or throw it out, there is an excellent chance it will recover. Now that you have re-hydrated it just leave it alone basically. Don't drench it every day and above all don't allow it to dry out again. Read [url=https://www.helpfulgardener.com/forum/viewtopic.php?t=1479]this[/url] for tips on watering bonsai. The chopstick/skewer method is pretty useful while you are getting used to watering and I do recommend that you try it.
Chinese Elms are tough customers and within a few weeks, possibly sooner, you should see new buds emerging from the locations of the previous leaf stems. Be aware that a tree with no leaves will not lose much water by transpiration and since it is in a cool location, loss from evaporation will be lessened as well. Just water as required using the guidelines posted above and keep your fingers crossed.
Make sure to stop back and tell us how things go for your tree, good luck.