Hey Hawken, that is from using too much oil. You want your cases to be slippery, but any excess oil will cause a dent. When I first started reloading, I had this happen. Then I read what the problem was, so I was less generous with the oil, actually wiping off if I get too much. You just want enough so your cases don't stick in your full-length die.
Oh, I can't answer your questions, per se. But I don't think so right off. After you fire those, your dents will be gone. But I would personally not use them if I dented them very badly.
That's my 2¢.