Apple Watch won’t turn on
My daughters Apple Watch ran out of battery within a couple hours after full night of charging. We charged it again overnight and now it won’t turn on.
Apple Watch SE
Question marked as
If you tried all the steps in:
If your Apple Watch won't charge or it won't turn on - Apple Support
Including if you still need help, contact Apple Support.
Then your best option may be to make an appointment at the Genius Bar in an Apple Store near you and let them look at it:
Genius Bar Reservation and Apple Support Options - Apple