Hi
You should not wear Apple Watch in the shower.
Your watch is splash and water resistant but it is not waterproof. You can, for example, wear and use Apple Watch during exercise, in the rain, and while washing your hands. Submerging Apple Watch, however, is not recommended. The watch should also be dried if it gets wet.
Apple specifically advises, for example, that the following may affect the water resistance of Apple Watch and should be avoided:
- Exposing Apple Watch to pressurized water including showering.
- Swimming or bathing with Apple Watch.
- Submerging Apple Watch in water for long periods of time.
- Wearing Apple Watch in the sauna or steam room.
Water resistance is not a permanent condition and Apple Watch cannot be rechecked or resealed for water resistance.
More information:
https://help.apple.com/watch/#/apd707b42a5e
Wearing Apple Watch - Apple Support