Good luck getting Apple to do anything about it.
When this happened to my wife, the Apple Watch got white hot and she had to tear it off her wrist to stop it from burning her. I documented everything including the injury. The Apple Watch itself showed no obvious signs of issues.
After a long process of trying to escalate this through Apple, I was assigned an unbelievably rude senior rep at Apple who literally yelled at me and insulted me over the phone. They actively did everything they could to deflect the incident so that there could be absolutely no acknowledgement of an issue with the watch.
When I told the rep I simply wanted to send the watch in for Apple to look at it, they refused. All part of the insistence that there was nothing wrong with the watch, if they accepted it even at my own expense, it would be like admitting fault, which they refused to do since there was a claim of injury. In the end Apple told me they would not do anything for me, and that it was a allergic reaction to the Apple Watch, despite the person having worn one for 6 years.
I even said to the rep, "If I hung up this call right now, went back on Apple Support chat and told them my watch isn't working I want to send it for repair, they would be assist me, no questions asked." and he responded "Yes I'm sure that's right".
They are undeniably actively covering up Apple Watch burn incidents.