What came first - the affliction or the white hair?
(13,3) “The Kohen will look at the affliction on the skin of his flesh, and if the hair (שער) within the affliction turned (הפך) white…”
Rashi explained that the hair was originally black and turned white within the affliction, and the word שער means a minimum of two hairs. But why did Rashi first explain the phrase “turned white” which is in the later part of the posuk, and only afterwards explained the word “hair” which comes earlier in the posuk?
But we can explain that Rashi is coming to tell us that the posuk means that the hair turned white within the affliction, that is, that the affliction came first and then the hair turned white. But how do we know that this is the correct explanation - maybe the hair was white before the affliction came? It must be that the word הפך refers to the affliction, that is, the affliction turned the hair white.
But maybe the word הפך refers to the hair, meaning that the hair turned itself white, and really the posuk means that it turned white before the affliction came? Therefore Rashi explained that the minimum of שער is two hairs, and so if the word הפך refers to שער it should have said הפכו in the plural. Thus we must say that the word הפך refers to the affliction, and the correct explanation is that the affliction came first.