I was on my third and final rinse last week, not really keeping track of the water temperature when I had filled the bagged, and realized something was wrong when I could feel the water enter. When I reached up and felt the bag, it was almost hot. And it hurt expelling. My body temp went up, heart started racing, and I started sweating like crazy. Jumped in the shower and turned on the cold, but that didn't help much.
Afterwards, I got on the phone to my nurse of a wife, who doesn't (didn't) know I take enemas every week or so, and explained. She advised to go back up and take a cold water enema, which I did, and it cooled me down fairly quickly.
In the mean time, I gave my GP a phone, and he said that unless there is bleeding, I shouldn't worry about it. It's been a week, with no ill effects.
Bottom line (haha), be vigilent on the water temp. (My boiler must have kicked in while I was filling the bag, giving the hot water system a jolt.)