People still haven't realized that Kaido only has monstrous vitality, but in terms of durability/ tenacity even someone like Izo/Kiku can hurt him. So, it doesn't seem impressive to me that Momo hurt him, now if the damage is highlighted by Kaido then it will be inconsistent.
I will pay my last tribute to my favorite character: Perorin!!! Hope we get more of your fight with the full spoilers.