Water ingress into an electronic wrist watch - temporarily put in freezer?

[e100]

It's going to take a week for the special tri-lobe screwdriver to arrive so I can take the back off and attempt to dry it out.
While I'm waiting, is it a good/bad idea to store it in freezing conditions so as to reduce the corrosion rate, or will the ice crystals do more damage as they expand while freezing?

[Rerouter]

put it in a box with some proper desiccant packets (Not rice!) and leave it on something that runs hot, e.g. a settop box,

Or even better go to a watchmaker, ask them to swap the battery for you and to not put the back cover on, will probably cost $20 for a battery swap,

[Ian.M]

Its important to immediately remove the battery so the circuit has no power (to stop electrolytic corrosion)  and get its interior as dry as possible as soon as possible to minimise damage.   Although freezing it to -20 deg C would slow down corrosion, you risk it destroying the LCD, and popping off or cracking any components on its PCB that have a lot of water trapped under them.

As Rerouter said, go to a jewellers that does watch batteries as soon as possible, preferably as soon as you read this, ask them to open it, remove the battery, and give it back to you with the case open.  However *DON'T* have them put the new battery in!

If the water was salty or heavily contaminated, odds are its going to need manufacturer's service or be BER.  The longer you wait to get it dried out and the saltier the water, the lower your odds of success.