I’ve always wanted to see a retcon on the “hot mask” thing so that it was intentional. It’s part of a ritual to give him increased magic powers, and sacrificing his face is the price he pays for that power. “Doom will sacrifice anything for power,” plays much better with his characterization than, “Doom is vain and also stupid.”
“To gain power, you could sacrifice your face.”
“My perfect handsome face? But I’m vain!”
“Uh, it now has a barely-noticeable flaw.”
“Then I’ll stupidly declare it’s ruined — so, okay!”
“How did you get that tiny scar, anyway?”
“I was too vain to correct a stupid math error.”
“You could say it really blew up in your face.”
“Kind of a recurring theme with me, yeah.”
You can of course argue that Doom would never say any of that. But that just raises the question: because he’s too vain to admit it, or too stupid to realize it?