See Avos D' Rabbi Nosson Perek 9:2, that Aharon was not the primary
talker (or perhaps, was not talkative generally?) and therefore his
punishment of Tzaraas (if it happened at all - see Sugya Shabbos 97a)
was not made clear (
i.e. the Tzaraas that he got for just a moment, was transferred to
Miriam).<br><br>The
Passuk does say "VaTedaber Aharon U'Moshe", not "VaYedab'ru", implying
that Miriam was the one who was more involved in the actual
stating of the Lashon Hara.