Is the prayer valid if drops of urine are discharged and a tissue is placed [there], and must the tissue be removed before or after the prayer?

Scholars differ on the validity of the prayer of one who prayed with impurity on their body or clothes, having forgotten about it at the time of prayer. The preponderant opinion is that their prayer is valid, and this is the view of the majority of scholars, based on the statement of Ibn Taymiyyah: "If one prayed with impurity on their body or clothes and did not know about it until after the prayer, repeating it is not obligatory, according to the more sound of the two scholarly opinions. This is the view of Malik and others, and Ahmad in the stronger of the two narrations, whether he knew about it then forgot it, or was ignorant of it from the outset; due to what has been previously mentioned, that the Prophet, peace and blessings be upon him, prayed in his sandals then took them off during the prayer when Jibreel informed him that there was harm on them, and he continued his prayer and did not restart it, despite that being present at the beginning of the prayer, but he did not know about it." Repeating the prayer as a precaution is better, to avoid the scholarly disagreement.