It's not sealed but there are electronics underneath. I believe there's also screw holes below for case fixings.
A tiny bit of water isn't going to hurt anything though, as a precaution just dry it out and tip it upside down for a few hours.
If no problems arise initially then it'll be absolutely fine. Electronics are far more resilient to water than people thing, and usually (Aside from premature corrosion, not to worry in your case) if the water bridges an electrical current it'll go BANG immediately, if it doesn't do this then just leave it for a bit and carry on...