Hard to tell for sure but it looks like either a die chip or a plating bubble. FYI, a cud comes from the rim like this:
Sorry it is not a cud which must be from the rim. The picture of the anomaly is not quite visible on the eye. It could be a few different things. Is it raised? Could you get a better close up.
Wait I did post correctly, I saw the example of furry frog and had thought you had sent a better pic, LOL.
how do I find out what it is or if it's worth anything, I have 22 total out of a roll of 50.. hope there worth something toward retirement...lol