Not finding a definitive answer here or anywhere else over a week ago, I decided to find out for myself.
On Friday, December 18, 2015, I reached into the microwave oven for a ceramic mug filled with boiling water. Although I’ve done so hundreds of times in the past at home without incident, there was something strange about the glaze on this particular Chinese-made “Starbucks” mug a a friend’s house, as it instantly caused a second-degree burn on the side of my right hand ring finger where it had pressed against the handle loop. It startled me so badly that I jerked my arm back, which caused boiling water to splash onto my hand, causing additional first degree burns. Within an hour, a large, painful blister had formed on the finger.
I did consider draining the blister after three or four days, but then thought, if I were careful and kept it wrapped with an adhesive bandage and change the bandage every other day, there was a chance I could keep the blister intact. I succeeded in doing so, and today, December 28, 2015, I’ve removed the bandage and the blister has shrunk to the point of being essentially gone. There is clearly a layer of dead skin that will need to wear away, or that I may need to trim away with scissors once it tears, but the tenderness in the area is pretty much gone, telling me that the skin under the blister has fully regenerated.
So, the answer is, “yes”, blisters do go away on their own, and it takes about ten days if they’re protected against damage.