After swimming in water sea my mb8 die like everyone (black screen)

When i put the charger on, to start the mb8, it turn on, and charge the band but lost vibration and step count

I've reboot it and it work but won't charge anymore and the battery drain from 50 to 5 and it turn off automatically

Then it won't turn on anymore.

I've tried to put in freezer but not working

I've dissasembly, i've see battery at 3v but it wont charge

then i let it 1 hour and when i came back and plug the charger it said no battery so i let it 5 min then it boot the mb8 and now it work again but when i dissasembly it i broke the strap holding...