Actually, I’ve known this for a couple of years, but I learned it firsthand last week while using the MIG welder at our shop. I was kinda in a hurry and ran several beads without a helmet on. About an hour later, my face started tingling like I had gotten sunburned. Two days after that, skin was peeling off my face like the Nazi bad guys at the end of Raiders of the Lost Arc. Maybe I could market this process as a “photochemical peel” to the narcissistic Hollywood types!