Welcome to Coin Talk. Clear photos of both sides of the coin are needed in order for anyone to help you.
Or used as a plug. Circle scratches from the turning of the threads to apply the pressure for the seal.
Sorry, but it's post mint damage, not an error. It was pressed into something. It did not leave the mint looking like that.
Off topic. It's healing. Found the tendon to bicep was also torn. First PT tomorrow. Thanks for asking. Now back to your regularly scheduled CT thread
Yes off topic but I hadn't heard and was concerned. Glad to hear you're on the mend. That coin almost looks like it was made into a button or a piece of jewelry.