What is the ruling on prayer if a piece of cotton was placed to block the exit of secretions from the anus, and then secretions were found on it after the prayer?

If the adhesive prevents the discharge from exiting to the external vulva, then the ablution is not invalidated, and the prayer is valid. However, if it does not prevent its exit, then the ablution is invalidated. And if you find discharge after the prayer and you are unsure about the time of its exit, then estimate its exit at the earliest possible time. If it is possible that it exited after the prayer, then your prayer is valid.