Suggest Remedy For Excessive Sweating At The Base Of Skull

Excessive sweating at base of skull. It occurs both during the daytime and while sleeping.The sweating can soak my pillow.I do not sleep on my back, I am what they call a belly sleeper. Thus sweating enough to soak the pillow would be excessive in my book.This condition has occurred off and on for the past four years.My doctor has run extensive tests and found nothing.More than likely in the next week. It will stop.Any suggestions that my doctor may not have considered?