iPhone Water Damage Help?

I have an iPhone 6S that I dropped in my pool a few months back. It sorta survived except for a few things. To get it back working I reinstalled al lithe software after wiping it and it worked. The only issue with the phone is every 20 or so seconds vertical lines crawl across the screen. To get rid of them all I have to do is click the off button and turn it back on. Any thing I can do to slow this down or completely remove the issue? I have been dealing with this for about 6-7 months.