There is no reason the copper IUD would affect your acne or skin at all since there are no hormones in it whatsoever. I’ve never heard that, and in fact the reason I wanted a copper IUD in the first place was because it doesn’t interfere with your body’s natural rhythms at all. Not sure what you’re referring to, but I find it extremely odd that someone would attribute their acne to their copper IUD (hormonal IUD is different though, and I don’t know much about its side effects).