the first question you have to ask yourself when determining a mint error, or PMD is: "how could this possibly have been done during the striking of the coin?" if you can get past this question, then the next one is "could this happen any other ways after it was minted?" once you have those questions answered, then you can determine if it's worthy of another pair of eyes or just PMD. you should be able to explain what you think it is and how it was caused by the minting process for question #1, if you can't get that far, then it's probably PMD which is 99% of the finds from circulation. what caused the PMD really doesn't matter. the raised edges around the dents means it was jabbed by something, and that didn't happen during the strike of the coin. if it were a strike through, the edges around the anomalies would not be raised.