Phone left in rain, now lines vertically across whole screen.

Nick Genco that is a repair you want to approach very carefully and not expect it to be successful. Water damaged phones are amongst the most difficult and least likely successful repairs. Any one part may have failed. This phone will be one of those that does not stand a good chance. There are so many things that went wrong right from the beginning. Rice is absolutely useless and does the same as doing nothing. It does not work. It does not prevent corrosion or shortcircuits. Turning the phone on, trying to use it, or trying to sync it, make it even more likely to short circuit. Of course, you can always give it a try. At least you'll get some experience out of it.

I suggest you treat it just like any other water damaged iPhone. The very first thing you want to do is to not try to restart, sync or otherwise try to use the phone. This may further damage your phone. The next thing to do is to clean it. Disassemble your phone using [this guide and remove the battery. Discard that properly, it is not reusable. Your logicboard requires that you remove all the EMI shields. If you do not, you will leave 80% of the board dirty and contaminated. Then clean it with +90% isopropyl alcohol. Follow this guide , and even so it was written for a iPhone 3G all the points are still pertinent to your phone. While you clean your board, check for any obvious damage, like burned or missing components etc. When it is properly cleaned, replace the battery. All these steps are to avoid delayed failure caused by corrosion. Once all this is done, reassemble your phone and reevaluate. The best way to clean would be via an ultrasonic cleaner, but I assume you do not have access to one. If you are lucky, then you only have a shorted out display assembly. Worst case would be damaged components on the logic board which cause the lines on the display. Hope this helps, good luck.