Mishnah Negaim 8:10: There is [a case] of [one] showing his Nega to the priest and benefiting, and there is [a case] where he shows and loses. How so? One who was decided [as impure] and then his signs of impurity went away, if he did not manage to show it to the priest before it spread over his entire [body], he becomes pure, for if he had shown it to the priest, he would have become impure [after it spread over his body]. A Baheret with nothing in it, if he did not manage to show it to the priest before it spread over his entire [body], he is [quarantined for] impurity, for if he had shown it to the priest, he would have become pure [after it spread over his body].

יֵשׁ מַרְאֶה נִגְעוֹ לַכֹּהֵן וְנִשְׂכָּר, וְיֵשׁ מַרְאֶה וּמַפְסִיד. כֵּיצַד. מִי שֶׁהָיָה מֻחְלָט, וְהָלְכוּ לָהֶן סִימָנֵי טֻמְאָה, לֹא הִסְפִּיק לְהַרְאוֹתָהּ לַכֹּהֵן עַד שֶׁפָּרְחָה בְכֻלּוֹ, טָהוֹר. שֶׁאִלּוּ הֶרְאָה לַכֹּהֵן, הָיָה טָמֵא. בַּהֶרֶת וְאֵין בָּהּ כְּלוּם, לֹא הִסְפִּיק לְהַרְאוֹתָהּ לַכֹּהֵן עַד שֶׁפָּרְחָה בְכֻלּוֹ, טָמֵא. שֶׁאִלּוּ הֶרְאָה לַכֹּהֵן, הָיָה טָהוֹר:

Mishnah Negaim 9:1: [The Negaim (diseased patches on skin, clothes, or houses that create impurity) within] a boil or burn make one impure after one week [maximum] through two signs: white hair or spreading. What is considered a boil? If he was wounded by wood or by stone or by [the heat generated by] crushed olives or the waters of [the hot springs of] Tiberius, [or] anything not because of a fire, this is considered a boil. What is considered a burn? [If] he was burnt by coals or by embers, [or] anything because of fire, this is considered a burn.

הַשְּׁחִין וְהַמִּכְוָה מִטַּמְּאִין בְּשָׁבוּעַ אֶחָד, בִּשְׁנֵי סִימָנִים, בְּשֵׂעָר לָבָן וּבְפִשְׂיוֹן. אֵיזֶה הוּא הַשְּׁחִין. לָקָה בְעֵץ אוֹ בְאֶבֶן אוֹ בְגֶפֶת אוֹ בְמֵי טְבֶרְיָא, כֹּל שֶׁאֵינוֹ מֵחֲמַת הָאֵשׁ, זֶה הוּא שְׁחִין. אֵיזוֹ הִיא מִכְוָה. נִכְוָה בְגַחֶלֶת אוֹ בְרֶמֶץ, כֹּל שֶׁהוּא מֵחֲמַת הָאֵשׁ, זוֹ הִיא מִכְוָה: