the damage could also be from the fall, not from the water... you could go snorkel with that thing :D
I also have a story to tell about a Samsung device and water... I own a Gear S3 watch and it's also waterproof. When I was at the Mexican carribean and went on a snorkeling trip, I forgot to put it off, snorkeled with it. When I realized, it was still on, my first thought was "FCK!!!" because I lost a non-waterproof fitbit years ago the same way. But then I was like "well, fck it, it should sustain that". An hour and a very beautify sea turtle sighting later after I got out of the water, the watch was still working but had very strange distortions on the display. Colors missing, pixels flipping, very strange. I backed up my data, switched it off and mentalle prepared to write it off. But two days later, it was like nothing had happened. I have the watch still, two years later, and it's fine.