is most likely to regress on its own as owing to the size, functional cyst is most likely. The pain you suffered could be due to the misplaced IUD. You should get a regular follow up with your gynecologist along with serial sonograms to follow the course of the cyst. If you wish to continue contraception
, choose those methods which allow ovulation to continue as suppression of ovulation may lead to cyst formation again. You may take analgesics and antispasmodics for pain relief. Please check with your doctor if you need a pelvic antibiotic.Wish you good health.