I couldn't go to the emergency dentist, because the only time they had left would have earned me a three-month sanction from the jobcentre. And the walk-in centre is not, as stated on their page, for dental matters.
So I went to A&E instead. I was intending on presenting it as a recurring infection that I was worried about. But as soon as I mentioned that it was in my gum, the agency-uniformed nurse behind reception told me to get out. Wouldn't listen to another word, didn't give me chance to explain how long this has been going on or why I was at A&E instead of a dentist. Just told me to get to a dentist instead, that it isn't that hard to a dentist appointment (the fact that I've been waiting since October for this appointment says otherwise), and trying to tell me that the emergency dentist is a walk-in service (I've used it enough to know that it really, really isn't).
I gave up and left when she threatened to call security on me. I couldn't even get her to call the staff nurse/matron/whatever her supervisor's called over. Meanwhile, my gum hurts more this evening than it did this morning, and I really don't feel well now.
tl;dr A&E receptionist hears "gum infection", refuses to listen further, kicks me out without letting me explain, am feeling worse now.