I grew up in/around my parents' electronics repair business and can tell you Yes, I've encountered water damage (many times) and no, it's not fixable. Even if it were fixable by a professional, the repair would cost more than purchasing a second-hand replacement.
It's now too late and the damage is done but your best bet would have been to immediately disassemble it as best you can, clear any surface water, dry it out (in a bag of raw rice in a warm place for minimum 24 hours), and hope.
Even if you got it working again the likelihood is that the life of the camera has been severely shortened and I wouldn't expect it to be reliable even then, the circuits are delicate so only a small amount of corrosion or a short in the wrong place and the device is done for.