Ok lets start by getting the phone out of the rice before you damage it
Don't Put Your Device in Rice. Here's Why...
What your discribing sounds more like impact damage than moisture damage. Sounds like youve damaged the LCD
However if it does happen to be water damage this should help first disassemble the phone Clean every connection with a soft toothbrush. As well clean the logic board; use a 90%+ IP alcohol for all cleaning. Now is the time to start drying out the phone. Set the screen in a desiccant or silica gel leave it in for several days moving it from time to time to get the max effect from the desiccant. Use a blow dryer on a low heat setting to dry the rest of the phone. Only use a hair dryer once you have cleaned the phone completely with the alcohol. Do not attempt to dry the phone if it’s still wet with water with the blow dryer as this only spreads the water. Replace the battery with a new one considers the old ones done. Clean again with IP alcohol let dry and when you think everything is clean and dry reassemble the phone (make sure to clean the contacts on the screen after removing from the desiccant). Once you've reassembled the phone it’s time to power it on. Hold your breath and hope for the best
This is Another guide that can be helpful