A Metzora has a stringency that the whole body must be shaved while a Nazir only must shave his head.
A Nazir must shave his hair with a razor when he completes his Nezirus.
According to Rebbi if a Nazir shaves his hair with a razor he transgresses two Mitzvos Lo Sa'aseh. (1)
If a Nazir shaves one hair he is punished with Malkus.
When a Nazir shaves his hair at the competition of his Nezirus if he leaves two unshaved hairs he has not fulfilled the Mitzvah.
If most of the hair of a Nazir is shaved during his Nezirus he must recount thirty days. (2)
The Leviyim in the Midbar shaved their hair with a razor.
The Leviyim in the Midbar required Tenufah (waving their bodies).
Bread must be brought with the Korban Shelamim of a Nazir.
The Rabanan hold that the prohibition of shaving the corners of the beard applies only to a razor. (3)
R. Eliezer holds that the prohibition applies even if the beard is pulled out with a tweezers.
A BIT MORE
1. If he cuts his hair from its root without a razor he transgresses one Mitzvos Lo Sa'aseh and if he cuts the hair partially he transgresses a Mitzvas Aseh.
2. R. Shimon Ben Yehudah says in the name of R. Shimon that if only two hairs are shaved he must recount thirty days.
3. A Metzora may shave his beard with a razor even though he is transgressing the Mitzvas Lo Sa'aseh of shaving the corners of the beard and the Mitzvas Aseh of Kedoshim Tiheyu if he is a Kohen.
MITZVAS ASEH AND LO SA'ASEH
A Metzora may shave his beard with a razor according to the Rabanan even though he is transgressing the Mitzvas Lo Sa'aseh of shaving the corners of the beard and the Mitzvas Aseh of Kedoshim Tiheyu if he is a Kohen. Although normally a Mitzvas Aseh does not override a Mitzvas Aseh and a Mitzvas Lo Sa'aseh however the Mitzvas Aseh of Kedoshim Tiheyu applies only to Kohanim and the Mitzvas Lo Sa'aseh of shaving the corners of a beard applies only to men not to women. Therefore it is not as stringent and the Mitzvas Aseh overrides it even though there is also a Mitzvas Lo Sa'aseh.
If a Nazir shaves his entire head with an ointment he is not punished with Malkus but he has annulled a Mitzvas Aseh. (Rambam Hilchos Nezirus 5:12)