Any matter admitted under rule 1.510 is conclusively established in the pending action unless the court on motion permits withdrawal or amendment of the admission. Subject to the provisions of rule 1.604 governing amendment of a pretrial order, the court may permit withdrawal or amendment when the presentation of the merits of the action will be subserved thereby and the party who obtained the admission fails to satisfy the court that withdrawal or amendment will prejudice that party in maintaining that party’s action or defense on the merits. Any admission made by a party under rule 1.510 may be used only as an evidentiary admission in any other proceeding.