Sorry for the late reply. Did you negotiate to have this medical bill removed from your credit report as part of your settlement? If you did not negotiate, unfortunately there’s not a lot you can do at this point. You can try sending what they call a “goodwill” letter. A goodwill letter is a letter you send to creditors asking them to request a goodwill adjustment to your credit files.
You can read more about goodwill letters here: http://credit.about.com/od/creditrepair/qt/Using-Goodwill-Letters-In-Credit-Repair.htm