i would pull the battery and allow it to sit for a few days for all the water to escape. I know I got a normal keyboard wet a little once and it would not function correctly until it was completely dry which involved popping it apart and using toilet paper to soak up any remaining water between the plastic layers and letting it dry for a day.
Now a laptops different from a desktop keyboard but letting it completely dry might resolve a few issues.
In addition, if you have a fan, set it up to blow air against the bottom or into the vent holes on the side to help speed up the drying. Maybe even on-top into the keyboard.
AS for the future, there are a couple things you can do. I don't know where you live but here you can pick up a can of scotchguard for a few bucks. Even cheaper would be some generic shoe waterproof sprays which would work just as well. Cheapest would be to keep a 2 foot long piece of plastic wrap in your bag, then when you anticipate water, simply wrap your laptop in it as well as you can. It should keep out most of the moisture. assuming the bag doesn't go underwater.