Why wont my home button work?

After droping my IPhone 4 in a pool, i put it in rice to dry, it worked fine except for the lcd screen. Everything else was fine. After i changed the screen and my home button to mach my new color, the home button doesnt work. i have tried to take it out and reinsert it, it doesnt seem to be broken but everything ive tried hasnt worked! Please help i havent had a phone all summer and schools about to start so i need to get it back up and running.