About 20 years ago, when I was 13 and had no clue about such things, I went windsurfing with my first 'proper' watch, a 21j Citizen. It said 'water resistant' on the back so I assumed it was ok. Anyway, the thing got totally ruined with water and started running about an hour fast every 5 mins. Distraught, I took it to an old watchmaker called Noel who used to be based in Shepherd's Bush market who took the watch casing off, blasted it with air, took out the mainspring, put into into a clear liquid (I assume it was lubricant), reinstalled it, adjusted it and it has been working fine ever since. The point to all this is that water damage to a mechanical movement is seldom terminal. The worst that can happen is that you need a complete servicing of the movement.