What if the Nesek spread during the first or second week?
Rashi: We can learn from the double Lashon "Pasoh Yifseh" that, even if it spread during the first or second week it is Tamei. 1
Rashi writes that Pasoh Yifseh teaches that if the Nesek spread during the first or second week, he is Tamei. We should know this already, for it says about both of them "Lo Fasah"!
Riva: If not for "Pasoh Yifseh", one might have thought that he is Tamei only if it spread and there are yellow hairs, but if only one of these occurred, he is Tahor. 1
Riva: I retract. Even without Pasoh Yifseh, surely even one Siman is Metamei. If not, the Torah should have written "Oh Lo Hayah Se'ar Tzahov"! (Seemingly, this is like R. Yoshiyah. According to R. Yonason, v' Lo Hayah