Battery replacement after water damage (even for testing?)

I had a Lifeproof case fail on me while at a water park (a bit frustrating as its less than eight months old) and there appears to be very little water that ever got in the phone (mostly around the sim tray and the home button)... Replacing the battery is listed as a must regardless of how much actually got on/in the battery area. Do I need to replace the battery immediately because of potential issues or can I use the battery (less than two weeks old unfortunately) to test the rest of the phone (I hate to throw money at a dead phone if I don't need to) and then buy a new one if it works?