[graeme]

>post-concussion syndrome

Isn't that akin to "long covid"? No one mistakes post-concussion syndrome for a concussion, and no one mistakes long covid for an acute infection.

We do have a formal name for long covid: PASC (Post-Acute-Sequaelae of Covid)

It won't catch on a regular name because it's unpronounceable, but it there for the scientific literature and those who wish to speak formally.

I'm open to there being a better way, but ultimately you need something people can refer to, as it is a common phenomenon.