IPhone 4 problem! Help! Screen went black!

Okay Guys. So my iPhone 4 phone screen went black. I was on Facebook, then I don't know what happens. Facebook exits me to the home screen, and when I try to go back on, it doesn't let me. I try other apps, and it still won't let me. The iPhone is about 3 years old, and I took care of it. I've dropped it a couple times, but no damage to the screen. It got a little damp once, so I put it in a bag of rice and that fixed it. I tried the bag of rice this time for 4 days. It didn't work. Any help would be appreciated. Oh and here's a pic of the phone.
http://www.flickr.com/photos/98032670@N02/?saved=1

Hold the home button and the lock button until the apple comes back on the screen. That should turn it back on

Hi! Perhaps your phone's screen cable inside went wrong or incorrect order because of throwing. Can it receive a call? If can am sure it screen problem. If can't maybe other hardware problem. I know you are here because you don't want to go to sevice repair but to make sure what happening please do. I suggest you connect it to pc to see or backup your data

You can do a hard reset on it, that's when you hold down the lock screen button and power it off. That should help you out

Mine has done this before. I hold the lock button and home button for an estimated 10 seconds or until it turns off. It will then turn back on or you have to turn it back on and then it should work. :) hope it works for you!

Could you try a force shut down and see what happens? To force shut down the phone, hold the on/off button and the home button at the same time until the apple logo appears on the screen. The phone will take it from there! I have had to force shut down my iPod before, it does not delete anything from it-- no personal message, contacts, or anything. Everything that was on your phone before the force shut down will still be on there. I know how frustrating this can be, good luck, I hope I helped!