Eventually I realized that the neighbours could probably hear us, so I had to pretend to be a grown up and overcome my intense desire to run away. I joined them to see what she was talking about. She kept pointing at him and groaning, but she was pointing at his head. I asked her to be more specific about what she meant (ok, really I just kept shouting WHAT? at her). “His nozzle, Mummy, his nozzle - there’s something in there.”
The penny finally dropped; I asked her if, perhaps, she meant nostril, not nozzle. Yes, she did. It turns out it was nothing to worry about, just a booger. And who knew dogs even had boogers? This dog ownership thing just gets better and better. Pass the wine.