If you dropped your phone in water, wrap it in a paper towel to absorb water. Putting it in rice does very little to nothing.
Also, do not try to switch on your phone unless you are absolutely sure it is completely dry. A short might occur and you risk further damage.
If you know how to, it is better to open your phone and clean it with isopropyl alcohol to displace the water.
However if you do not have the right tools or skills, take it to a phone repair specialist.