When a person has on the skin of his body a swelling, a rash, or a discoloration, and it develops into a scaly affection on the skin of his body, it shall be reported to Aaron …
The lesion is a tzaraat. The person with the tzaraat is a metzora.
The Gemara asks: Is leprosy not an affliction of love? Didn’t we learn in a baraita: If one has any of the four signs of leprosy (Leviticus 13) they are nothing other than an altar of atonement?
Rabbi Yohanan … consoled others by displaying that there is an element of intimacy with God that exists in suffering …
While they are not classified as afflictions revealing God’s love for the person thus afflicted, they are however, described as “an altar serving as stepping stone to atonement for the character weakness that the afflicted person has to overcome.”
Rabbi Adiin Steinsaltz
an ordinary person is not worthy of tzaraat. … to receive such a mark is truly indicative of a high level, of which the receiver must be worthy.
So long as a person does not stop acting improperly, the tzaraat continues to spread.
Rabbi Steinsaltz discusses different kinds of sins afflicting spiritually advanced persons.
One type is scorn towards those who do not live up to high standards — when the scorn becomes a source of pleasure it is a tzaraat.
Another type is miserliness. It involves persons “who take on the fear of God.” In the process of this spiritual awakening, they may become so fearful of doing wrong that they give up important parts of themselves and feel that they are deadening their life.
… Such a person, who is dying little by little, continually reinforces this downward spiral by telling himself that the more dead he becomes, the more he deserves his fate. He thinks that his dark, morose attitude to life is a form of devoutness … Holiness and all that stems from it are characterized by energy and vitality, while tzaraat is a form of death mark, sapping the very life force from the metzora who bears it.
A third type of sin involves inappropriate rebukes that the person thinks are good deeds rather than sins.
Also, there is a fourth type — haughtiness — where a person’s perception of their high level prevents from seeing the errors they make.