In the middle of trying to draw a Jon I stopped to think about the hypothetical placements of his post-Prentiss worm scars.
Most of the time I see artists draw them just scattered across his face, but weren't the worms said to mostly burrow into flesh at first? I doubt larvae like that could just "bite" and burrow through bone, even with the surrealist horror aspect included.
I like to draw the majority of Jon's face-located hole scars on his cheeks. That would mean at one point the worms got in his mouth.... gross......