My iphone 4s won't turn on and its been on charge for hours. What do I do?

4 days ago I went sledding with my friends and dropped my phone in the snow. I picked it up, inspected it, and it seemed like nothing happened. When I got home I tried to listen to music while it was charging but no sound came out of the speakers. I plugged in some earphones and it worked perfectly fine so I just wore earphones anytime I wanted to listen to something from that point on.

2 days ago, my phone turned off at 50% and I was so confused. I plugged it into a wall charger for about 10 minutes and it didn't turn on, so I plugged it into my PC and still nothing. I let it sit for about an hour and then tried to plug it into my PC again, this time the red battery symbol showed up. From there it worked fine.

Today I woke up and it was off, but it was on charge all night. I've had it plugged into a wall charger for about and hour and a half now...still nothing. What should I do?