It looks like a die gouge. It would only be worth a substantial amount if two bidiots got into a bidding war over it. Chris
I keep hearing about these bidiots, I don't know who they are, but they're welcome to come check out my stuff! Oh, and I'd vote blister. Like this one I just found: Although I think the OP's blister is in a more interesting place. I call him, "Unicorn Abe"
you say you will trade me a 1909 s vdb for it you got yourself a deal lol just kidding im gonna keep it