Of course we've seen it before and when his face got fixed (For good?), but have we ever seen his full face after the mask Burn? Everyone says that it's supposed to be horrific, but have we ever actually seen It? I heard that there was an older issue of Namor that showed us. If so, which one, and can anyone provide a Scan? Thanks.
I don't think we are supposed to know what Doom's face really looks like because nothing would do it justice. Even the recent Secret Wars reveal wasn't a full unhooded view. That said, there have been at least a couple of occasions where an artist has come close.
Doom 2099 #25 showed a future Doom that looked suitably deformed after returning from an undefined battle that hosed his armor
FF v3 #31 showed Doom mostly unmasked/scarred when he reclaimed his armor from Reed Richards.