You just dropped your photo camera or a lens in water; What can you do now if it was not weather-sealed or water-tight?
The first thing to do is to remove all electrical power source. Electricity does ugly things to metal and electronics. So, start by removing the batteries right now. You may be able to dry them separately, but you’d better be ready to buy new ones (the heavy humidity may damage them too much even if they survive).
Next, you need to dry the camera. As soon as possible. First, use sponge, them some absorbing paper (possibly toilet paper, you will find it nearly everywhere in the world). Try to shake the camera a little, but not too much (you don’t want to drop your camera in the water again!)
After that, a little heat will help. Water will evaporate more easily with warm temperature in a dry air. Avoid at all costs to leave the photo camera on whatever heating system you may find. But a few hours in a warm room will help…
But this will probably not be enough. The finishing touch will be to dip your camera into a bag of rice. This is about the same tip as the one used for the salt in your kitchen or on your table: a little white rice will capture the humidity from the salt crystals and leave it dry. Put your camera in an uncooked rice bag for a week; This may not be very elegant, but it will be do the job for a very little cost.
Only then will you try to insert a battery again. You are never sure that it will work, but all these steps will have tremendously improved the odds.