From what I can see it appears that the mint mark has taken a small hit and with copper being a soft metal it moved. There looks like a small amount of displaced damage to the lower left part of the S mint mark.
The coin looks to be die deterioration damage. Look at the closeness of the "L" in Liberty , usually a nice indicator. As the coins are minted, the force over a Large number of them, causes the metal dies to flatten out over use, so deteriorated lettering can be on the front die or the back die can be the die that was needed to be changed. The force and shape of the die is designed to "push" metal from the center to the perimeter, so the most visible is on the outer parts of the coin. Jim
