Hi Michelle,
You can wear the patch just about anywhere. I always wore mine on my upper arm, (the right one only, as it felt weird on my left arm), but be careful about putting it on any area that sweats more, as it will then be more suceptable to falling off. Your back is fine, tummy, etc.
Sometimes (in the beginning) I was embarrassed to have it show on my arm, as I wear sleeveless tops a lot, but later I really didn't care what people thought. In fact, a lot of people were in awe that I quit, (strangers even) and would ask me questions about my patch...mainly asking, "Do those things really work?" Well, here I am almost 2 years later, and yes, they do work!!!
Good luck!
Deda