There can be many reasons why you dropped your iPhone, maybe you were bending to pick up something and it just slipped out of the pocket or you might have dropped it accidentally. There are many cases where the dropping of the iPhone has done a permanent damage and it needs a replacement. Although Apple states on the iPhone Warranty (PDF) that “Service may not be available if your iPhone has been damaged due to accident or abuse”. So in that case you need to be sure whether your iPhone is under warranty or not.
Lets see what all things can happen when you drop your iPhone and what all can be done to save your iPhone:
1.) I Dropped my iPhone on the floor : The structure of the iPhone is such that it can sustain impact from a certain height but if your iPhone is dropped from a height of more than 3 meters then there are chances of getting cracks on the screen and dents of your iPhone does not have a strong casing. There have been cases where the iPhone vibrator had stopped working. The LCD screen might get misaligned or cable inside the phone that conects the screen to the board had come loose and the screen appears to be dim or it might not even startup.
In all the above cases there is a very good chance that your warranty is not void, so go to apple support.
2.) I Dropped my iPhone in Water: This is the worse case than above as Apple does not give any warranty on iPhone if it fell in water. The iPhone can be easily detected it has fallen in water or not. The two images shown , one shows a pink colored bottom of the jack plug this has been changed irreversibly form white when it came in contact with water.Water contact can not only harm the speaker and vibrator of the iPhone but if water comes in contact with the battery, the whole iPhone circuit will be corrupted.What you can do if your iPhone drops in water, is remember DO NOT TURN IT ON or press any button, try to dry it up using a hair dryer and keep it under dry conditions. People have even used putting their iPhones in a bag of rice and it had worked though i do not understand the logic of it. In case it doesn’t start, you can try drying it up for weeks and then going upto Apple store for replacement. Many times this thing has gone undetected and people have got a free replacement. check this out
For all the above cases it is best to buy the Apple care insurance which costs on $40/year and your iPhone will be replaced for $250. For more information on iPhone insurance check this link.
Last of all there are some cases which cannot be helped such as these Click here. Make sure that yours isn’t the same case.