Liquid damage minimal damage screen replacement iPhone 4S

My iPhone 4s recently took a swim in a glass if Mt. Dew. Only the top 1/4 was submerged and I had an otterbox commuter series case on it. Not the completely sealed one. The damage is minimal. The only issue I have is discoloration and "ghost images" on the screen. For example, I can see the dark colors of the previous app used on my home screen or even the next app I use. Should I replace the LCD and digitizer assembly? Does anyone think this will fix the "ghost images" I am seeing? Other than that, the phone is fully functional and battery life has not been affected. Thanks in advance!