I see a red "!" on your Apple Watch

If this happened during or directly after a software update, try following an Apple article at https://support.apple.com/en-us/HT204776 for instructions on how to force restart in that situation. Let me know if this works for you, if possible.

Ah, that’s unfortunate. I recommend that you should take your Watch to your nearest Apple Store, then, seeing how it looks like it’s your last option.