I had the exact same thing after dropping my phone TWICE. I put it in a ziplock bag, without the battery, sim card, nor sdcard, and then in the freezer. In total it took about 7 days for the blue spots to clear, but I took it out every 24 hours to check on its progress. I just took it out and let it dry off for about 10 minutes, then put the battery in and turned it ont to check how much was clearing.
If that doesn't work, replace the LCD.
MB525 - Bayer Camera - cm-11-20131124-NIGHTLY-mb526