Hi
It may help to turn Water Lock on and off again in order to expel any water from inside the speaker:
Use the Control Center on your Apple Watch - Apple Support
Apple Watch Series 3 models are sufficiently water resistant that they can be used, for example, when shallow water swimming.
However, in respect of showering (and bathing), note that Apple specifically advises against:
- Exposing your Apple Watch to soap or soapy water - such as when showering or bathing.
- Exposing your Apple Watch to high velocity water.
- Exposing your Apple Watch to dramatic differences in temperature and/or humidity.
- Wearing Apple Watch in the sauna or steam room.
More information and detailed handling instructions are provided by Apple here: