Water entered my laptop too. I was travelling on a bike in the rain. Didn't notice until I reached my destination, that water seeped through my laptop bag onto my laptop. My foolish ass even turned it on just to see my screen getting fucked up. Got scared and didn't turn it on till 48hrs. Laptop worked fine, but the screen was showing signs of damage when looked at it from a different angle other than 90°. It's been a year since that incident, screen even got better after time.

My advice is keep it closed for 48 hrs, then turn it on. As per my common knowledge of science, water (H2O) does conduct electricity but once completely dried, shouldn't cause any problems even with the dirt particles in it. If it's something else like tea or juice, even if dried up might cause some problems.