He'll most likely be fine. It happens often enough while giving them a bath. They have the same reflex as humans or any other animals, to exhale and splutter it out if they get water in their nose. Very occasionally it can lead to a URI, but there's nothing a vet can do other than treat it if it develops. Watch for a drippy/bubbling nose, wheezing, or any other signs of a URI, but the chances are pretty low. Mine are each bathed weekly, and about half of the baths end up with water in the face - no URIs so far.