I had this 1957 wheat cent for some time and was wondering what kind of error is this? it is definitely not PMD the arrows point to what looks like to me through the loupe a letter or something between the "B" and the "E" and that looks like an "I" on the back of the "E".
That is a die chip, often referred to as a BIE error because it looks like another letter. Keep up the hunt!
It is relatively common, especially given the date. But I have seen them sell for a few bucks on ebay, so there is a little bit of demand for them because of the location.
They appear on most date and mintmarks from the 50's but especially 1957D. There are also other breaks such as BEIR which are not so common. And there are different areas such lower quarter, top quarter, center or full BIE. There's even a blob BIE where the break spills into the B & E. And a sausage BIE that extends past the top and bottom in a curve resembling a sausage.
this is not a 1957D is just a 1957 no min mark. mine spill into the B and E. does that make a difference?
From what I can see yours is a straight BiE against the E that spread from wear. a blob is a break that takes out part of the ajacent letters. But it's still a good find.
Good Luck. Check any 1954S cents. There is an error called a San Jose. It's a die break under the S that forms a J.