Dropped iPhone 5s in Sea. Dark Bright Spots and Blue screen

So i fell into a sea a month ago, i had phone disseambled for 3 weeks, some spots were removed but still its bad quality. After i got it back turned full brightness and white wallpaper and puted it to rice for night. When i waked up turned on to charger and after barely using for 5 minutes blue screen with white lines. Should i change screen, do something else or just forget? Because sea water probably hitted the processor and etc already. One tech guy told me he could change the screen but said that it might die any day.

What should i do?