It would be helpful if you had posted FULL IMAGE photos of the entire coin. Is the edge normal? @paddyman98, @Fred Weinberg @JCro57 probably know.
It's a fairly common occurrence - I believe it's a bit of extra metal from the planchet's edge that got folded into the inside of the rim. I'm not positive of the cause, but it is not rare, and is not significant or unusual, imo.
Not sure. on cuds-on-coins, in nickels 1950-1969, there's nothing like yours exactly... yet this is a common area for die chips from the letters and numbers to the rim, or small cuds and even cuds on coins seems to be on the fence on if it's cud or chips, because some are filed as cuds but clearly they are chips. check out CU-5-1960D-08 to 11 http://cuds-on-coins.com/jeffersonh-nickel/ like I said, it's not yours, yours has similarities but big differences, like more of "it" but not as defined. Maybe it's a lot of die chips on the edge of the die but the collar was still good? that area is tight, in fact if the coin had more wear that takes down the rim, you wouldn't even see that anymore.' fred may also be on track here, folded over rim finning.
