It is impressed upon you when undergoing chemotherapy that your immune system will be compromised and that you should take any indication of bacterial infection seriously. Hence when I woke in the early hours and realised that my impacted wisdom tooth - having lain three quarters revealed but dormant for some forty years - had sprung into action, I was in a state of mild panic. Daylight is a great healer and so was the Ibuprofen. I then negotiated the NHS Direct helpline (sent there by the dentist's out of hours message) and from there to a dental nurse who rang me back, and finally a dentist. She suggested that a wisdom tooth that had caused no trouble for so long probably wasn't infected but that I might have a tiny piece of food stuck somewhere. Another good clean, pain relief if necessay and warm salt mouthwashes were recommended (I guess hot Bovril fits the bill too) - and of course I already have the antiseptic rinse with which I was issued and that I use night and morn. Panic over.
P.S. Something hard, black and sharp manipulated itself out of the side of my gum this morning; the dentist was right. Inflammation now subsided.