There's a possibility that your data's gone but it's not certain. I once left a spare HDD in a box with the cover open near a window. It rained heavily and water had collected inside the box, completely soaking it. I didn't notice it for several days. I dried it out thoroughly and, lo and behold, it worked fine !!
The key word here is "thoroughly". It's not enough to get it visibly dry. The water would have penetrated all the tiny spaces between the component pins and copper tracks on the circuit board.
The important thing is NOT to test it until you're sure everything has dried out completely.
If you'd like to try what I did : Gently dab off as much water as you can with a dry cloth and/or cotton-wool. Then dry it as much as you can with a hair dryer. Take care not to overheat anything, but don't be too timid either - those components can easily stand 70 degrees C or more.
Don't keep blowing on the same spot for more than a few seconds at a time. When you're afraid of overheating, stop, let it cool down and then start all over again. Make sure you blow every crook and cranny, including the connector pins.
Even after you think you've dried it as much as you can with the hair dryer, DON'T test it yet. Expose it to open air for several days, with the circuit board side up, to let all the remaining moisture evaporate, occasionally blowing it with the hair dryer again. THEN test it.
If this fails, then the data recovery guys can probably still recover your data. The platter housing is hermetically sealed and your data is probably still intact.
Good luck.