Unless it's on the nerve accumulation in the chin, the friction isn't enough to cause any brain trauma (a KO punch to the chin overloads the nerve accumulation forcing an auto shutdown by the brain). I'm biased to think it only spread her lipstick.
I do like the idea of the cheat code of unlocking O-Lin. That immediately allows Luffy to go after Kaidou.
I'm personally hoping for continued expansion of anime-only fighting, so we might see the highlights of all the different clashes. We haven't seen Marco/Perospero the longest I think, so Oda creating the template for the anime to expand upon for the various allies (excluding the Scabbards). Since I have a different view on Big Mom, I'll say the chapter ends on something with Big Mom getting angry and ready to fight seriously.
Hmmm...I actually don't think Franky's motorbike directly hit Big Mom's chin, but neither her dome. More of her face, maybe?
A second panel focusing on the hit also made me think Oda is trying to tell us that it's not just a normal hit that would anger Big Mom, but trigger something that already occurred before. May not be the case, though. :