(Mishnah): If a Nazir was Safek Tamei (Mes), and was a Safek Metzora Muchlat, he may eat Kodshim after 60 days, and drink wine and be Metamei after 120 days.

This is because the Aseh for a definite Metzora to shave overrides the Isur for a Nazir to shave, but a Safek Metzora who is a Nazir may not shave.

(Gemara) (Beraisa): This applies to a 30 day Nezirus. If he accepted a year of Nezirus, he may eat Kodshim after two years and drink wine and be Metamei after four years.

(Beraisa): He shaves four times:

The first time, he brings Tziporim, Chatas ha'Of, and Olas Beheimah. (The Tziporim (birds) are not Korbanos. They are used in a ritual to permit a Muchlat to enter the city after his Tzara'as went away.)

The second time, he brings Chatas ha'Of and Olas Beheimah;

The third time, he brings Chatas ha'Of and Olas Beheimah;

The fourth time, he brings Korbanos Nazir Tahor.

Whether or not he was a Muchlat, whether or not he was Tamei, he does not transgress bringing invalid Korbanos.

The first time: if he really was an (absolute) Metzora, the Tziporim were brought properly. The Safek Chatas ha'Of is not eaten, rather buried. The Olah is a Nedavah;

He cannot shave after only seven days (like a Muchlat whose Tzara'as went away), lest he was not a Muchlat, rather a Tahor Nazir, who cannot shave until finishing Nezirus.

If he was not a Muchlat, but was Tamei Mes, the Chatas ha'Of was obligatory. The Tziporim were not offered in the Mikdash, so there is no Isur of offering them needlessly. The Olah was a Nedavah.

If he was not a Muchlat, and was Tahor, the Tziporim were no problem (like above). The Chatas ha'Of was not eaten, rather buried. The Olas Beheimah was part of the obligatory Korban of a Nazir.

Question: He must bring also a Korban Asham! (A Metzora must bring an Asham before he may eat Kodshim!)

Answer: The Beraisa is like R. Shimon, who says that he may stipulate (if he does not need an Asham, it should be a Shelamim Nedavah).

The second and third times, he need not bring Tziporim, for he already brought them!

Both times he brings Chatas ha'Of. (The second time,) perhaps he needs it because he finished the seven days of Sefirah of a Metzora. (The second and third time,) perhaps he needs it because he was a Tamei Nazir.

The fourth time, he brings Korbanos Nazir Tahor and stipulates as follows:

If he was initially a Nazir Tahor (i.e. he was not a Metzora, and he was not Tamei), he brought his obligatory Olah the first time, so the Olah he brings now is a Nedavah;

If he was a Muchlat and was Tamei, all the Olos he brought were Nedavah, and the current Olah is obligatory.

In either case, he also brings the other Korbanos Nazir Tahor.

If he was Safek Tamei and definitely a (Muchlat) Metzora, he may eat Kodshim after eight days, and drink wine and be Metamei after 67 days;

If he was a Safek Metzora and definitely Tamei, he may eat Kodshim after 37 days, and drink wine and be Metamei after 74 days;

If he was definitely Tamei and a Metzora, he may eat Kodshim after eight days, and drink wine and be Metamei after 44 days.

(Beraisa) Question: When a Metzora Nazir Tahor shaves at the end of Tzara'as, can this also count for Tiglachas (upon completing) Nezirus Taharah?

Answer (R. Shimon bar Yochai): No. At the end of Tzara'as, he shaves in order to grow his hair again (so he can shave after Sefirah); when he shaves upon completing Nezirus, he need not grow his hair again.

Question: This applies to shaving before Sefirah. When he shaves after Sefirah (he need not grow his hair again), this should also count for the shaving upon completing Nezirus!

Answer (R. Shimon bar Yochai): No. A cured Metzora shaves before he brings Korbanos. A Nazir shaves after bringing a Korban.

Version #1 - Question: This shows that the Tiglachas Metzora should not also count for Tiglachas Nazir Tahor; but it should count for Tiglachas Nazir Tamei (who brings Korbanos after shaving)!

Answer (R. Shimon bar Yochai): No. A Nazir Tamei immerses before shaving. A cured Metzora shaves after immersing.

Version #2 - Question: You have shown that Tiglachas Metzora after Sefirah does not count for Tiglachas Nazir Tahor; but the Tiglachas before Sefirah should count for Tiglachas Nazir Tamei, since both must grow hair to shave again!

Answer (R. Shimon bar Yochai): The Tiglachas of a cured Metzora can never count for Tiglachas Nezirus.

It cannot count for Tiglachas Nazir Tahor, because a cured Metzora shaves to grow his hair, and a Nazir Tahor need not grow hair again.

It cannot count for Tiglachas Nazir Tamei, because a cured Metzora shaves before immersing, and a Nazir Tamei shaves after immersing.