Well, if it was paid in full, with no balance remaining, I don't think you have any leverage to do much. It will be on your reports as a paid collection for 7 years. Depending upon the laws in your state, either 7 years from DOLA (Date Of Last Activity) which is when they cash the check, or DOFD (Date Of First Delinquency).
However, given that it's a medical bill, getting goodwill from them might prove a bit easier than getting it from a bank.
My two cents, for what it's worth, if you aren't planning a major purchase like a car or a house in the next few months, let it lie. Keep an eye on your credit reports. It's conceivable it could drop off once they cash the check, or within a month or two thereafter. Not very likely, but it does on rare occassions happen.
If not, you might try goodwilling it in a few months to try and make it go away.
At this point, you aren't really as concerned about your scores as you are seeing the collection drop off your reports. One of the Big Three's 3-in-1 credit monitoring services is much cheaper for day-to-day, week-to-week, or even month-to-month, pulling of your reports. I use TransUnion's TrueCredit. It's $11.21, if you sign up via the Walmart Financial Services link.
