The worst thing you can do to a device that’s been in water is to try and turn it on without it drying out. I’m guessing your phone is not one that’s designed to be waterproof. Or as waterproof as it can be that is. You can try putting it in a bag of rice to see if you can draw out the water from the phone. I would keep it in the rice for a few days. If that doesn’t work then your only other option would probably be to disassemble the phone and clean up any corrosion that may be on the logic board as this will cause the phone not to work. Corrosion occurs because of the water. If you are not comfortable taking your phone apart then I suggest taking it to a local repair shop to see if they can help you out.