accidentally and stupidly dropped phone in sink while it was running. Phone works, but blue stuff on bottom of screen. Left in bag of rice for 12 hours, no change. Should I leave in longer or try something else?

Yesterday evening I accidentally dropped my iphone 5s in the sink while it was running. I immediately removed it and it started acting funny (sreen would turn on and off on it's own). It stopped doing that and was working fine. However, shortly after when I had time to really look at it, I noticed blue-ish stuff on the bottom of the screen. I turned it off and put it in a ziploc bag with rice for over 12 hours. Turned it back on today and the blue stuff is still there. Anything I can do? Should I put it in rice for longer? My concern (aside from the blue stuff driving me insane) is that the phone may suddenly die on me at any moment if there's still water in it and it's only a matter of time. Will an apple store do anything? I can't replace the phone. I haven't had it for very long, but it is definately out of warranty period (not that apple covers water damage anyway). Any help is much appreciated!