Or HaChaim on Deuteronomy 24:8/אור החיים על דברים כ״ד:ח׳

1 השמר בנגע הצרעת, "Take heed of the affliction known as Tzoraat, etc." According to Shabbat 132 on our verse the meaning is that a person afflicted with this plague must not remove the afflicted section of his skin in order to remove the evidence of his disease. The reason why the Torah added that we should remember what G'd had done to Miriam is intended to remind us of the true source of such an affliction and to remind those who think they can cure it by cutting off the skin where it appears that they are on the wrong track. The way to get rid of this affliction is to remove its cause, i.e. to rehabilitate a character fault which caused it in the first place.