OP here: just to say that a) it was a small lap dog, but very ferocious. The bus was very crowded so I was pressed up against the dog, holding my phone with one hand and the other by my side (it bit that one); b) I had washed my hands just 20 minutes before getting on the bus (in the LADIES toilets), so they must have smelled on soap or of nothing at all. I checked afterwards and I couldn't smell anything unusual; c) thankfully my stop was pretty close so it wasn't long before I could treat it Thanks for all your concerns in the comments! It's really nice to hear them- it's healing quickly and hopefully there won't be a scar :) xxx