water damage to my s4, home button won't work. HELP!

i dropped my galaxy s4 in water. i put it in rice for about almost a day. i read online i had to keep it in for 3 days, but i couldnt wait any longer. when i took it out i put the battery and my sim card back in when i turned it on the home button didnt work and only the top of my power button worked. i took it apart again and put it into the rice, but now that the bottom part of my phone doesnt work and is completely dead i realized i most likely wont be able to charge it. how do i fix my home button?