Negative commandment · Lo Ta’aseh #308 of 613
Not to remove the signs of tzara’at
שלא לתלוש סימני צרעת
The verse · Devarim 24:8
הִשָּׁמֶר בְּנֶגַע־הַצָּרַעַת לִשְׁמֹר מְאֹד וְלַעֲשׂוֹת כְּכֹל אֲשֶׁר־יוֹרוּ אֶתְכֶם הַכֹּהֲנִים הַלְוִיִּם כַּאֲשֶׁר צִוִּיתִם תִּשְׁמְרוּ לַעֲשׂוֹת
“Take heed in the plague of żara῾at, that thou observe diligently, and do according to all that the priests the Levites shall teach you: as I commanded them, so you shall observe to do.”
The Rambam’s words
Not to remove the signs of tzara’at, as [Deuteronomy 24:8] states: "Be very careful concerning signs of tzara’at."
שלא לתלוש סימני צרעת, שנאמר "הישמר בנגע הצרעת" (דברים כד,ח).
Why · Sefer HaChinuch #584
To not detach signs of tzaraat (a Biblical skin disease)
“It is from the roots of the commandment to hint that every person should tolerate whatever pain and whatever punishment G-d, blessed be He, punishes him and not rebel against them.”
Who & when
“And this prohibition is practiced in every place and at all times by males and females, such that one who contracts tzaraat and recognizes the signs of his tzaraat is not permitted to cut them off.”
Where in the Mishneh Torah
Hilchot Defilement by Leprosy הלכות טומאת צרעת