The phone was submerged in water but started working after putting it in rice for several days. It doesn't seem to charge as well and sometimes shuts off on its own. Can a new battery be installed?
The biggest issue with water in a phone is you can never be sure you get all of the moisture out. I always keep those little silica packets that come in shoes and other packages but a bowl of rice is helpful. Before you powered the device on you would have been better served to take it in for repair to see if the phone was truly dry. Even if it was it still likely shorted a circuit inside. Water resistance is one thing Apple should add to the iPhone but I double we will see that.