I suffer with a sweaty head when I sleep.
I have suffered with a sweaty head whilst sleeping for 2 years.
Sweating around the head and neck area is an efficient way to dissipate excess heat so that your body will remain at a constant core temperature of around 37 degrees. It is possible that either your bedroom temperature is too high or your covers are allowing you to retain too much heat. It is better to have a coolish room so that you can lose heat around your head and neck without the need for sweating. Stress, alcohol, caffeine or even a late warm drink may also be the cause. If you are concerned or feel unwell then it would be worth seeking a medical assessment.