For anyone who is still unclear of the effects of a TN attack:
Imagine having powerful electric shocks suddenly, out of nowhere and with no warning, in your face. In between each shock there's a sensation of burning, as if your cheek or jaw is actually on fire. There is no pain like it - not childbirth, not a tooth abscess, not the pain of RA, nothing (and this is backed up by neurologists, it's not just my perception).
Remember that this pain comes on completely out of the blue. There can be triggers, but equally it can happen spontaneously. You're walking around Sainsbury's, say, and suddenly you're having electric shocks in your face. The sheer unexpectedness of it means you drop what you're holding/scream/sink to your knees as @PhilCornwall1 describes. That's mortifying enough, but if the pain continues for more than a few seconds, which it usually does, you can lose consciousness.
Shop staff then call an ambulance because if someone screams and keels over in your shop, that's what you do. They also have to clean up any mess you've left. Paramedics arrive, you explain the situation, they may take you in and give you the serious hardcore pain relief you can only get in hospital (although it's worth remembering that for neurological pain, things like opiates don't work). If you don't lose consciousness, you still have to find your way home while in the throes of an attack. Then you have to hope and pray that it's an isolated attack and not the start of a flare, which can go on for weeks and can mean hundreds of attacks a day, with no pain relief.
Now imagine knowing that this will never get better or go away and will only get worse over time. The meds you're on don't halt it and don't stop all attacks and eventually, they won't work anyway. Then your only option is brain surgery, the results of which vary immensely (from a few months to a few years relief). But it always comes back. The surgery with the best outcome is very invasive and carries a 1 in 100 risk of death, and a higher still risk of stroke/paralysis/loss of speech.
That's TN. That's what people with TN live with. And most of us can't wear face coverings because triggering an attack - or worse still, a flare - in public is an absolutely terrifying thought.
When people with TN tell you they can't wear a mask because they're doing everything they can to avoid the risk of an attack, believe them.