Dropped iPhone 5 in water, screen not working

I slipped into a puddle on yesterday with my iPhone 5 in my back pocket. It had both a gel and hard shell casing on it. I wiped it off about four seconds after landing in the puddle, although I didn't take it out of the case. It didn't seem that wet, and the screen was working fine--in fact, I even took a few pictures with it shortly thereafter.
I gave the phone to my friend to hold for about 45 minutes while I found new pants to change into. When she gave the phone back, it had turned itself off. I turned it on and the apple logo lit up, flickered, had a few lines of code on it, and the screen flickered into gray bars. Only the left half of the screen worked so I had to use the home and lock button to shut it off. It kept turning itself on, however. I took it out of its case and aired it out.
When I got home I used the bag of rice method and didn't charge nor turn it on for about 24 hours; I turned it on tonight and everything works fine--Siri, the audio and buttons. I even checked the water damage mark on the side of the phone and found it untouched. However my screen won't respond to my touch at all, and has two faint blue and red lines from behind the screen.
If everything works well, is it possible I can just get the screen replaced? Or is this a software damage? Lastly, when is it ok to charge it without worrying about frying the circuits? All the other features of the phone (that I can access with my phone locked) work impeccably. I would appreciate any and all help.

I think some 3rd-party places can fix it for you, but I doubt it with that much damage. If you take it to the Apple store I'm not sure if they would help you either.