It looks to me like damage from a coin rolling machine. You'll often see that on coins at the end of machine-wrapped rolls. For future reference, if you want useful help it would benefit everyone to include clear pictures of the whole coin and give more information in the title- date, mint, and denomination.
Honestly, we need better than potato quality photos to do more than guess. It's a reasonable guess, but...
1. In focus - shoot the ENTIRE coin square on so the entire coin is in the focal plane 2. Some light on the coin 3. Crop the image to just the coin - we don't need to see the quality nor construction of your dining room table
Then you can add detail shots of whatever you are asking about.
In this case "what are the circular grey marks on the reverse?" - the more you make us guess, the less helpful the responses will be.