Watch stuck in swim lock mode

I suggest you make an appointment at the Genius Bar in an Apple Store near you. If that is not possible, then contact Apple Support. Either way:

Genius Bar Reservation and Apple Support Options - Apple

To turn off Water Lock mode;

turn your Digital Crown away from you in one continuous movement until the animated water droplet fills the circle on the screen. Your Apple Watch will then start beeping and vibrating multiple times. This is to allow any water in the speaker grill to escape.

Manually clear water after swimming

1. Touch and hold the bottom of the screen, swipe up to open Control Center, then tap .
2. Turn the Digital Crown to unlock the screen and clear water from the speaker.