Phone water damaged but doesn't switching on

You should disassemble your phone and remove the battery as soon as possible. Next clean its motherboard and parts such as cable ends and anything acceptable to corrosion(metal). You can use a high grade Isopropy alcohol (90%+) and a toothbrush to clean the parts. Rice will not do anything in helping revive a water damaged phone. The Isopropyl alcohol helps remove corrosive minerals left behind by water when it dries. If left uncleaned corrosion can build and cause more undesirable damage. You can also see if a repair shop in your area specializes in water damage and uses an ultrasonic cleaner if you do not feel comfortable doing it. Also water and batteries are not friends. The battery is usually one of the first components to fail after water damage. So it is very highly recommended to replace the battery. So try cleaning the parts as I mentioned and replace the battery. Once everything is cleaned and a new battery is installed, reassemble the phone and see if it powers on.

So leave the rice in the cupboard as it does not remove corrosive minerals and is useless because of that. It's not drying the phone out that's important, it's removing any corrosive minerals from the phone. The sooner it's properly cleaned the better.

There are guides on this site and YouTube that can help show how to clean a water damaged phones. I hope this helps and best of luck.