Kinda neat, if you count the number of lines in the dent it matches what should be on the missing part of the rim.... Not sure if it is an error or not though....
If the coin is bent in the slightest, it's post mint damage. If the obverse devices are flattened, then it is post mint damage. The coin is round and the obverse is normal and not bent, post images of the obverse and we will go from there.
Here is a pic of the obv. Coin is flat not bent, and is round. Like I said not sure if error or "PMD"
Sorry, just PMD. You can see the rim is damaged (i.e. the coin is not round like coop suggested), for example.
It isn't round. The line you see on the rim was there till the coin was damaged. If it was a struck through error that area would not be affected. The coin would be round if the coin was struck in the collar. Yours doesn't show the rim in tact. As to what it was damaged with, we may never know for sure.