Shingles live in the dorsal roots of the spine. So applying a patch along the spine on the side effected, is the most helpful.

You should use a patch every day, 12 hrs on and 12 hrs off.

I used them for over 2 weeks, on my MP nerve pain in my right thigh, and by using every day, the nerve calmed down after many years of over-firing, and went into remission. They don't work instantly either, but over several days you will notice improvements.

These patches work by slowly releasing lidocaine into the area, which then blocks the sodium channels in the nerve axons to prevent the signals from moving to the brain. Not using every day reduces the lidocaine and may not be strong enough to
get the job done.

Where on the back depends on your shingles presentation.
Dermatome maps show which nerves from the spine go where...
http://www.backpain-guide.com/Chapte...culopathy.html

For shingles pain don't put the patches at the endpoints of the map. For example, the blue gray color from lumbar area, go to the feet. Don't put a patch on the feet (that shows that color), but do put it over the lumbar area of the back. It will work better. Sometimes Lidoderms don't stick well... so you may have to tape it down.