if you lower your CPC on Google - and it doesn't work, and then you raise the CPC on Google adwords - will you go back to where you were listed before?
Depends on how long between the time your lower then raise it back up. One day shouldn't make a difference. Weeks or months will. What you have to keep in mind is that things don't remain static. Advertisers come and go. They improve their ads. They change their CPC. Their QS as well as yours will have changed, in fact, it changes by a minuscule amount for every search. All this will determine what your position is and how much you pay.
It is not sure that you will regain or go back where u listed before .. it depends upon your CPC bid or competitors CPC bid ... means it will consider how much you pay for your ad and what is your current position in inorganic search..... it is not sure that you will get your position where you listed before wether increase your CPC or decrease your keywords list........ because advertisers change their ads CPC or Budget time to time according to requirement.....
you'll be fine to try a lowered bid, Google themselves have stated that quality score is not adversely effected by brief changes