Yep, as P&G said. Keep it aside out of a 2X2 and watch its progression to a full blown rotted bubble.
Not sure about a plating bubble as it isn't discolored around the "blob" or sunken, and it appears to be over the 3, like something dropped on it. Have you tried a acetone soak and testing it with toothpick?
Plating blister. You can see a small breach in the plating so there is a good chance there is corrosion occurring, which may explain the size. Not an error of any kind
You're 1982 coins post was a very good one Pam. Remember post-1982 most are anomalies, pre-1982 more errors fewer anomalies. Thanks for posting the '93 it is an interesting anomaly. Good luck.
What does that zinc scent smell like? Lol, it’s a blister from the copper coating that will one day pop and turn into an ugly black spot. Darn zinc coins.