Get him to extract the tooth tomorrow. Are you in Scotland ? If you are registered with an nhs dentist in Scotland they have a legal obligation to see you / have an arrangement in place so other dentist will see you within 24 hours in such a situation. I am sure it is the same in England / Wales .
Google your local nhs trust or whatever it is called. See what they say about emergency dental care.
Also what was your dentist planning on doing about the other decayed teeth?
In great pain, had an inlay.... new type of crown thingy fitted to a back double 2 weeks ago, hurt like bugger on fitting.Never settled and got worse. Im nhs excemp btw. My nhs guy is only in x1 a fortnight!! They took me in as an emergency 1 week later with their private lady who did x ray, massive abscess, high dose anti biotics now. Due to see nhs guy in morning, anti biotics done nothing, in agony. Lady dentist said tooth too far gone for root canal, prob need to loose it plus x ray showed 2 teeth next to it gone aswell. My problem is the nhs guy used up all his hours....! Can only work for next 3 weeks then practice cant have nhs till next March!!! No other dentists in my area are taking on nhs, cant go further afield as dont drive as have epilepsy. wwyd....any advice would be welcome, plus in the morning not booked for treatment but in pain then he not in for 2 weeks, a joke. Dont want more anti biotics as cant see the point???? oh dear sigh