Go to the Genius bar and try and explain your story, if you're lucky, the Genius will take your word for it and replace it no problem. If the Genius refuses to do so, call Apple Support and talk to someone there. If you have a history of buying Apple products (they can look you up with your name/Apple ID) they're more lenient and understanding. I was lucky in that regard. I had my 3G replaced which had tripped the bottom dock connector sensor AND the inside submersion sensors. I thought I'd give it a go and see what Apple could do for me since I was a loyal customer. Honestly, I was surprised that they decided to swap it out. Very nice people at the Support center. You have nothing to lose, might as well try it out. If your HEADPHONE and INTERNAL liquid submersion activators are not pink, the Genius will more than likely swap it out, the bottom dock connector can easily get tripped by random stuff. When I was going through the process of getting my liquid submerged 3G swapped out, the support person was telling me that the liquid sensors only get activated under a certain amount of water... meaning you have to get a certain amount of water on that sensor for a certain amount of time... but who knows, that's probably just Apple mumbo jumbo to feed the ignorant people.
Best of luck, I thought I'd share my story so you know that you're not in a doom and gloom situation!