As long as you have not cranked the motor with the combustion chambers full of water, you should be pretty safe.
Drain the oil, change the filter.
Start it, run it, watch the oil colour carefully.
As the motor heats, the oil will slowly clear as the water fraction is boiled off.
If the oil colour shows signs of steadily worseing (it will turn a mustard colour), then you are still leaking water into the motor somehow.