The body mechanism for crying under water works just as fine above as below the water. So you can cry tears, they would just be mixed with the rest of the water.
Most of us cries for a reason, which is probably caused by something emotional happening. This means we breathe heavily when we cry, an as you can’t breathe underwater, you would end up drowning from swallowing too much water. So you would most likely end up dead, unless you have an air tank and a mask.