I did everything a website said not to do.

1.) Thank your friend from saving you the embarrassment of having put your phone in useless rice. Rice does nothing for water damage and is a horribly pervasive myth. Good thing your friend is smart enough to know better than to put a phone in rice.

2.) Smack yourself in the face for powering on a wet phone.

3.) After that, either throw the phone away, go to a professional, or figure out how to DIY address water damage--which means: Learn how to open your phone and disconnect the battery. Remove motherboard and clean with alcohol and a toothbrush. Allow opened phone to airdry for a few days, or help it out with a hairdryer on low. Then reassemble once you can no longer see or smell any alcohol and troubleshoot individual parts from there.

@grg as you've noticed from the previous answers, a lot of things went wrong with your attempt to save your phone. Number one lesson to learn here, is that rice does absolutely not do anything. It will only provide you with a false sense of security and makes you think you are doing something good. It is a waste of valuable time you could've spend cleaning your phone properly.

You can try to see if there is a chance. Smartest thing to do at this point would be to send it to somebody that is specialized in water damage repair. Where you send will of course depend on your geographical location. You can always try and see if you can do it yourself. For now you must consider your phone as destroyed anyway.

The very first thing you want to do is to not try to restart/sync the phone. This may further damage your phone. The next thing to do is to clean it. Disassemble your phone

For step 2 you can use a hot air gun and some suction cups. You must remove all the EMI shields of the logic board. If you do not remove those you are not cleaning the board properly. Clean everything with +90% (no less than 90%) isopropyl alcohol. Follow this guide, and even so it was written for a 3G iPhone, all the points are still pertinent to your phone. Pay particular attention to the SMD components, check for charred, missing or broken components. You can then dry the board in an oven or equivalent at 220deg F (not higher;-) for a few hours. Best way to clean it would of course be through an ultrasonic cleaner. Consider professional help with that When it is properly cleaned, replace the battery. All these steps are to avoid delayed failure caused by corrosion. Once all this is done, reassemble your phone and reevaluate. You can only determine what damage your phone has after you've cleaned it properly.