What is the ruling regarding prayers performed after waking up and finding wetness, without knowing whether it is semen or not, and without recalling a wet dream, and given the uncertainty about the nature of this wetness after several days have passed?

The preponderance of probability is considered equivalent to certainty by most scholars. Therefore, if it is highly probable that the wetness is maniy (spermatic fluid), then ghusl (ritual bathing) becomes obligatory, and the prayers performed before ghusl must be made up. This is because ritual purity is a condition for the validity of prayer, and ignorance of the obligation of ghusl does not negate the need for making up prayers, according to the majority of scholars. If the number of invalid prayers is unknown, then one must continue to make them up until the discharge of one's obligation becomes highly probable. This is contrary to the view of Ibn Taymiyyah, who holds that whoever neglected a condition out of ignorance of its obligation is not required to repeat the act. However, if it is not highly probable that the wetness is maniy, then ghusl is not obligatory. In such a case, it suffices to wash whatever parts of the body and clothes were affected, and to pray in clean clothes.