Plz tell meh .-.
They are probably more marks resembling whiskers then actual whiskers.
The better question is why Boruto and Himawari have them.
Makes you wonder if Mito's kid, Tsunade's Parent also had whiskers?They have whiskers because they inherited them from Naruto, that's all.
If Mito's kid had whiskers like Naruto but Tsunade didn't even though one of her Parent's is Mito's kid then I am guessing being a Jin is also a factor in carry down said whisker traits.They have two whiskers compared to Naruto's three. So after two generations, Kuruma's power would be so diluted that the whiskers will be gone.