Said R’ Shimon: When [is this true]? When it is exactly [the size of] a lentil; [if] it was larger than a lentil, the extra area is a symptom of expansion for the inner [nega], and the outer one is tamei. [If] it contained a dull white blemish smaller than a lentil, it is a symptom of expansion for the inner one, but not for the outer one.

There are twenty-four extremities on the body that do not become tamei because of michyah: the tips of the fingers and toes, the tips of the ears, the tip of the nose, the tip of the body, and a woman’s nipples. R’ Yehudah says: A man’s [nipples] as well. R’ Eliezer says: Also warts and hanging skin do not become tamei because of michyah.

These are the parts of the body that do not become tamei because of baheres: inside the eye, inside the ear, inside the nose, or inside the mouth; [in] folds [of skin], and [in] folds [of skin] on the neck; under the breast; the armpit; the sole of the foot; the nail; the head, and the beard; a raw boil, burn, or wound [lit. a boil, or a burn, or a wound that are rebellious]. [The above-mentioned parts of the body] do not become tamei because of negaim, nor do they combine with negaim, nor does a nega spread onto them, nor do they become tamei because of michyah, nor do they prevent him from [having the status of] turning completely white. [If] the head or beard became bald, [or if] the boil, burn, or wound developed a scab, they become tamei because of negaim, but they are not combined with negaim; a nega cannot spread into them; and they do not become tamei because of michyah, but they prevent [the status of] someone who turns completely white. The head and the beard before they have grown hair, and hanging skin on the head and on the beard, are judged like skin of the body.

The following are beharos that are tahor: [Beharos] that [a person] had before the Torah was given; [that were] on a gentile who converted; [or] on a new-born child; on a fold [of skin] that became revealed; on the head or on the beard; on a raw boil, burn, or wound [lit. on a boil, or on a burn, or on a wound or on the rebellious ones]. If the head or the beard then became bald, or the boil, the burn, or the wound partially healed, they are tahor. [A nega appeared on] the head or the beard before they grew hair. They then grew hair, and [subsequently] became bald, or a boil, burn, or wound that did not yet scab, then a scab formed, and [the boil, burn, or wound] healed, R’ Eliezer ben Yaakov renders [these cases] tamei, since they began and ended as tamei, but the Sages render them tahor.