First, to what part of the credit report are you referring: the public record that is the judgment, or the trade line for the underlying account?
The trade-line will be re-aged because you paid it, that action materially updated the status of that account with new activity. But if the trade-line shoes paid as agreed, it really isn't that damaging to your credit.
If the judgment has been paid, you should be able to file either a Motion to Vacate Judgment, or the creditor may file a Satisfaction of Judgment. Once that is done, the public record that is the judgment may be removed.
With some exceptions, the FCRA § 605(a) provides that a civil judgment cannot stay on a credit report more than 7 years - paid or not. It used to be, prior to the FACTA being enacted in 2003, that when you paid a judgment the clock reset and the 7 years started again. That is no longer the case. You should consult a consumer law attorney to see if there is something about your situation that might fall within one of the exceptions.
The answers to these questions may be different depending on your individual circumstance and should not be considered as legal advice or the establishment of an attorney-client relationship.