Apple Watch series 3 overheating and not turning on

My Apple Watch series 3, is covered by warranty, I wanted to know if my problem was covered or could be fixed. My watch went flat, as I was away and didn’t have my charger, it didn’t go on charge till 24 hours or so later, it the charged but became very hot on charger. I then took it off charge to cool it, now it is just a black screen and won’t charge. It won’t force restart or anything either. Please help!!!