Awwwww, cute story. Was Ladybug your sheltie?

I assumed that Jez felt something when she hit the nettles, because she did recoil. However, there's a very large spectrum of pain tolerance in dogs, with the working/sporting groups tending to not feel or ignore sensations that would definitely deter more tender breeds. Wolves and huskies are the most pain-tolerant of them all, of course.