Now, if you're out and about and decided not to carry any rice or silica gel packets with you, that's fairly understandable. Instead you may want to invest in a Bheestie product -- little bags designed specifically for saving your electronics in these moments of crisis. Have one on hand, drop your phone in, and hope for the best.
The prospect of unplugging for more than 10 minutes may terrify some, but it's certainly preferable to shelling out the cash for a completely new piece of equipment. At the very least, you should wait 24 hours, but 48 to 72 is preferable. Those silica packets need time to absorb all the water. Use this time to read a book, catch up on Netflix, and worry.
After the waiting period is over, get your phone out and see if it still works. It may not turn on immediately, but charging it for a few hours could do the trick. Water damage probably isn't covered by your plan, and most phones are equipped with a strip that changes color when exposed to water, so saying "It just broke" won't do you much good if you're trying to get a free replacement.