That would be a lamination error. Yes it’s worth a little extra, but don’t plan on retiring as it’s only a few extra dollars. Nice one though, so put it in a 2 x 2 flip and hang onto it.
Why is it silver colored though? To me it looks like it’s something stuck to the coin and the rest was peeled off. What’s the dark gunk stuck to the back of his head?
This date on a Lincoln Cent has a zinc core so that’s what you’re seeing. The silver spot is lower on the coins surface than the rest of the coin so nothing is stuck on the coin. I have no idea what that black spot is.