IPhone 5C screen freezes and fades to black?

So I got into the pool and stepped on something. I looked down and saw my phone. If i had to guess i would say my phone was submerged in 2 feet of water for about 6 seconds. After taking it out I immediately wrapped it into a towel as that's all that was available at the time. I tried to turn it on about 4 hours later and nothing happened. I decided to not turn it on for the rest of my vacation which lasted a week. I attempted to charge it, and when it turned on it seemed normal up until the point in which the phone's screen froze where it was and slowly faded to black, some areas losing color while fading to black. If anybody has had this issue and knows how to fix it I would be extremely appreciative.

You need a new phone.