Jewish law required the person to show his healed skin to the priest. The priest would then allow him or her to return to the community, to be with other people.
The law of Moses required that someone healed of leprosy give a thanksgiving offering to the priest. When the priest accepted the gift, people would know that the person had been healed.
This can possibly refer to 1) the priests or 2) all the people or 3) the critics of Jesus. If possible, use a pronoun that could refer to any of these groups.