Classmates, you first confirm whether the charge is full, my Bluetooth headset has also been like you said, but a little bit of heat is normal, wait for half a minute to charge and confirm that the charging light is gone, indicating that the charge is full, restart OK.
If it is very hot, there is a problem (it is useless, it is best not to charge again, put a period of time to try again).
Hope to help you!