Is it just me or is there a second face next to Lincoln? If there is a second face would it just be die deteriorate or machine doubling? If anyone is wondering the second "face" is visible with the naked eye. Looks very creepy like a ghost
It appears to be incuse to my eye. If so, and assuming it's not damage, I would suspect some sort of struck through that, by chance, just happens to somewhat mimic the lines of the face.