I don't see it - where exactly should we be looking for the die crack? (I see a bag-mark to the right of his ear)
I see a very fine 'stain' line - but based on the one photo, it doesn't look like a die crack. Can you shoot another photo or two of it?
Best pick I can get. The line on the head is clear. I believe a stain would have some color in it. Of course I could be wrong.
"Hey, what kind of crack is that?" Seriously though, with the lighting on these images, I can't tell if that squiggle is raised or not. If it is, it's a die crack. Who sneezed on this coin? The black spots seems to be from aerosolled sputum.
Not a whole lot. The "currency" of errors or varieties is usually "obviousness". When things are subtle and hard to see, demand suffers, and with it, price. There surely are "specialists" for this kind of material, but not being one myself, I'll leave room for them to speak.