It is not a cud; it is a small die chip. (A cud is a die break that includes the rim and extends into the field.) Your coin with a small die chip is interesting but it would command little, if any, premium.
Phew!! That was close! I thought for sure nobody was going to squash my inexperienced enthusiasm and wonder with a pedantic diatribe! Thanks for helping me dodge that bullet! Boy, that was lucky! But please, a little more condescending next time. We wouldn't want any optimism to grow back now, would we?
So what do you want? Do you want us to tell you that you found an incredibly rare and valuable error when you did not? I will try to remember not to answer your questions in the future so as not to offend you. Have a nice day.
Check out my album, I have posted a 1991D with a really nice die chip, similar to yours. Very cool looking, but worth a dime.
Thanks for the pic and the tip! Yours looks a lot better, by the way, but I do have one that looks like tears on his cheek. (boo~hoo tears) Also pretty cool.