The 111th mitzvah is that the metzora is commanded to have his hair shaven. This is the second purification procedure, as explained in the end of tractate Negaim.
The source of this commandment is G‑d's statement (exalted be He), "On the seventh day, he shall shave."
We already mentioned previously the statement of our Sages, "Three are required to shave, and their shaving is a mitzvah — the nazir, the metzora, and the Levites."
The details of this mitzvah are explained in tractate Negaim.
Now we will explain why the shaving of the metzora and his bringing the sacrifices [that complete his purification] are counted as separate mitzvos, while the shaving of the nazir and his sacrifices were counted as just one mitzvah.
In the case of the metzora, there is no connection between his shaving and his sacrifices. The goal which is accomplished through shaving is different from the one reached through bringing sacrifices. This is because the metzora's purification is dependent on his shaving [unlike the nazir]. In the sixth chapter of tractate Nazir, our Sages explained, "What is the difference between a nazir and a metzora? This one's (the nazir's) purification is dependent on the number of days, and the metzora's is dependent on his shaving."
Once the metzora has shaved and completed the second stage of purification, he no longer conveys tumah like a sheretz, as explained in the end of tractate Negaim. He remains in a state of being m'chusar kippurim [lacking complete atonement and forbidden from consuming sacrifices] like others who are mechusarei kippurim [until they bring their offerings], as explained there.
Therefore, the goal of his shaving is to purify him from conveying tumah like a sheretz, [which is accomplished] whether or not he brings the offerings. The goal of bringing the offerings, however, is to complete his atonement, like other mechusarei kapparah, i.e., a zav, a zavah, and a yoledes.
We explained previously the Sages' statement, "There are four categories of mechusarei kapparah," and explained there that the nazir is not included among them. This is because all his actions together, i.e., shaving and bringing offerings, allow him to drink wine. One is not sufficient without the other, the shaving connected to the sacrifice and the sacrifice to the shaving. Both together accomplish the single goal of allowing him those things which were prohibited during his Nazirite period. Our Sages said in the sixth chapter of tractate Nazir, "One who shaved and brought the offering, and later found it to be invalid — his shaving is invalid and all his sacrifices are ineffective." This shows that the shaving is conditional upon the sacrifices and vice-versa.
It is also explained in Tosefta, "A nazir whose time period has ended may not shave, drink wine, or become tameh meis" until he finishes the complete tiglachas taharah procedure as explained in the sixth chapter of Nazir, i.e., shaving by the door of the Ohel Moed, throwing his hair under the pot, and bringing the sacrifices, as explained in Scripture.
You will find that in most passages, our Sages refer to his bringing the sacrifices as tiglachas ["shaving"]. We see this clearly from the language used in most cases in the Mishneh, "One who says, 'I am a Nazir and it is my responsibility to shave a Nazir,' " [the latter phrase] meaning that he will bring the sacrifices and offer them on someone else's behalf. This shows that tiglachas is an expression referring to bringing the sacrifices. The reason for this is that they are part of it [i.e., the tiglachas procedure], as we explained, and everything together removes the Nazirite status and allows him to drink wine. Tiglachas tumah, however, is part of the mitzvah, as we explained previously.
