My Apple Watch is not working after swimming

We need a bit more info than that;

What model of phone is it and what version of ios is it running?

What model of watch is it and what version of WatchOS is it running?.

What troubleshooting steps have you tried?.

What errror messages are you receiving?.

Were you able to turn the water lock off?,if so try this;

If your Watch won't charge or won't turn on

I would recommend contacting apple support here;