It is entirely possible for slamming your jaw into your front teeth to result in a concussion,

however, it would require a third part that is currently missing from the equation - a force multiplier, such as an uppercut, or similar force vector (falling chin-first onto the top of wall/tree branch, or catching a knee in a football game).

If the head isn't moving with enough backwards/forwards linear force to bounce the Jello off the insides of the skull, or to distort the differing layers of Jello density via rotation forces (Diffuse Axonal Injury from a left hook, or high speed car accident), then the current version of the laws of physics state the symptoms have not been caused by blunt-force trauma.

There's been a bunch of crap happening in the world for some years now and now some Gollum-looking pillock is willy-waving with nuclear threats

This is has caused/is causing global levels of collective trauma, meaning everyone's stress responses and cortisol levels are all over the shop - with concomitant inflammation responses affecting the body and mind.

This is likely to be impacting people who have previously had a concussion / PCS more-so than those in the general population without a history of head-trauma.

I've recently ordered some more Curcumin extract to try to address this inflammation response, however, I've also found that curcumin can also play around with how I respond to fighting off colds. Several journal articles point towards curcumin's anti-inflammatory qualities being due to inhibitory effects on Cytokines and Interleukins. The rub being that, while high levels of some variants of these inflammatory markers are bad for the brain (and are now being increasingly linked to mood disorders), inflammatory proteins are also a normal part of the body's response to fight off viruses..

Neuroinflammation: The Devil is in the Details - PMC