I had the EXACT same thing happen to my last dog Abby ... I put the liquid revolution on her neck and within seconds she was screaming in pain and freaking out ... called the vet ... oh, yeah, that happens sometimes WHAT??????
It took almost 2 months for the gaping wound to heal properly and for her fur to grow back.
Never used anything like that since - I'll stick the holistic methods that have worked best for me over the last 7 years