Well, if it's running fine, other than some cosmetic damage, you should be fine. If you notice any sort of problems come up with it (screen flicker, clicking sounds from the hard drive, fan running constantly) take it in to the nearest Apple Store as soon as you can.
Apple notebooks are rather robust, I've seen time and time again. I had a friend with a 15" MacBook Pro accidentally drop a 20 pound barbell on it. The poor thing had a dent and the superdrive slot was bent up pretty bad, but it still ran like a champ.
You should hopefully not have any problems, and if you do encounter anything, just nip it in the bud.