Greetings Lippertg,
If you seed a red lightning bolt on your Apple Watch, it's best to complete the steps in the resource you used to reach us.
"If your watch requires charging, a red lightning bolt
appears on the screen. (You might need to press the side button to make the watch face appear.) When your watch is charging, the red lightning bolt
changes to a red lightning bolt inside a ring. If your screen is blank or the charging cable icon appears on the screen, charge your watch for up to 30 minutes. " If your Apple Watch won't charge or it won't turn on
If the issue continues, contact Apple directly to Get Support.
We hope this helps!
Sincerely.