We applied Hartz brand phenothrin (not to be confused with permathrin, for dogs) ointment to our cat Bobo.
Very soon after, Bobo began scratching at her neck and ears, and her head and ears started twitching.
We washed her off with Dove dishsoap, which we knew to be the best thing to get this kind of stuff off (ASPCA poison control recommends this method), and thought she would probably be okay after that because she seemed to calm down and rest and act normal/want petting, etc.
The next day we came home from work to find her ears and head twitching much worse than she had before.
ASPCA recommended a 2nd bath, so we did that (with much more Dawn this time) and Bobo started to get better over the next few hours. We also washed down our other cat, who seemed a little groggy from the poison (and who has had similar minor reactions to Frontline), but not twitching or scratching like Bobo. Bobo had a rash for a few days and proceeded to get better over the next few days.
I recommend the ASPCA animal poison control center (open 24 hours). 888-299-2973. We have called them twice and in this instance, it may have saved our precious Bobo from neurological damage. It costs $50 (thereabouts?) per call, because they don’t have public funding, but it is a great service, and they were very helpful.