my mother gets this and over time, from watching when it happens, I have a couple of ideas about why it happens. However, your first step should be to see a PCP to check your blood pressure, hormones, heart, etc. Make sure you are essentially healthy (or at least relatively so), first.

 

Assuming there is nothing medically wrong with you, I think you hit the nail on the head. It happens when you're overtired or not feeling well. for my mother, it is the exact same thing, and as far as I can tell, it is her body's reaction to being pushed beyond its limits. There does seem to be some connection to outside temperature, as well - she has fibromyalgia and is heat sensitive so what happens less in the winter. Mostly, however, it seems to be related to her pushing herself too hard. Once you stop working, and have had some time to rest, try to get into the habit of paying close attention to your pain and energy levels and respecting the messages your body tells you. You haven't been able to do that for a long time. I believe your body finds way of telling you what it needs and when its messages get ignored, it trots out the really big guns. For you, it may be sweating buckets.

I've lived with this kind of embarrassing and annoying sweating for 20 years. My doctor told me that prednisone changes the sweat glands in the face and head region and people who have taken high doses of or long term (which I have done both) prednisone usually end up with facial/head sweating that never goes away. I always carry a folded tissue with me to dab my head and go for hairstyles that don't look awful when my hair gets wet. I get it anytime I stand for more than a minute or two, or when I overheat from activity (like getting dressed in a hurry) or get the cold sweats. it's worse with some meds like SSRIs, or Mtx, which cause hot flash type symptoms themselves. I've also heard it can be fixed sometimes by surgery to the sympathetic nerves in the area affected (face, palms, feet, etc.). I hate it but have learned to live with it. I actually saw a great little hand held fan last night on The Voice - Cee Lo was using it and it had a covering over the blades (unlike some of the little open foam blade, battery held versions that I've tried). I was going to look it up and see if it was affordable! This is always why I hate summer in the South and love cooler weather, I tend to have less problems with overheating and sweating!