Looks like a small circle What coin are you showing? Can we see the entire obverse and reverse of the coin?
Can we please see more (better) pictures of the area of concern?? Some type of damage if I had to guess.
Honestly that’s the best photo I could get. It’s not noticeable to the naked eye I have to hold it up sideways under the microscope to even see it.
Here's my assessment. If it's too small to see with a loupe, then it probably won't catch the attention of collectors. Just an anomaly or Pareidolia.