My Apple Watch 3 won’t turn on or charge after going swimming today
So I noticed after going swimming today my Apple Watch 3 will not charge nor will it turn on or reset. No cracks or damage to the watch
Apple Watch Series 3, watchOS 6
Here is some good discussion and guidance about that topic:
About Apple Watch water resistance – Apple Support
https://www.applemust.com/the-apple-watch-water-damage-guide/
It might be best to have it serviced:
watch Repair - Official Apple Support