That does look strange. Can you weigh it? Some cents in 1982 were zinc with a dash of copper spewed on it, and some were copper, tin, zinc. The former should weigh about 2.5 grams, while the latter should be around 3.11 grams.
Looks like The 'Orange Peel Effect' from worn die. Link below explains it well. http://www.error-ref.com/orange-peel-texture/ Edit: Decent pictures btw! When you post though, can you post right way up so we don't have to get a crick in our necks looking at the coins please....? Thanks
My other thought, if the coin was copper plated zinc(Which it is) was plating blisters, BUT the effect is too evenly spread, so my original diagnoses of orange peel effect from worn dies still stands imo...
There is no mm, is just a trick of the light, look at the original pics, you can see it isn't there, so perhaps a nick or reflection off something (edit: small plating blister).