Omg ! My iphone fell in a bucket full of water and stayed in there for like 5seconds before i grabbed it .. So after screaming about it cuz it woulnt turned on and my phone was soaked in water my mom told me to put it on a bag of rice and left it there for anout to weeks and took out the sim and guess wat , now it works good again so happy ! Especially cuz ididnt have insurance on it :P
There is a possibility that it may be able to switch back on, though it will not stay on for long. You can switch it on by long pressing the "Power" button. However, the screen may appear blank when switched on due to the damage caused when it fell in water.