Think of the hygrometer as a clock. If the reading is false on the beginning all you need to do is adjust it to the correct reading and thereafter it will give you the right time, and in the hygrometer's case, the right humidity. Analogs tend to get out of whack easily when moved around, so what you tell us is not uncommon. It does concern me that you say that the needle didn't move at all. I will advise you to test the calibration the way we recommend on our website, using moist salt and a Tupperware container or Ziploc bag. That way you will be able to see the hygrometer reading without having to open the container and releasing the humidity. You will be surprised how fast the hygrometer reacts to a change of humidity, and it is possible that when you removed the wet cloth the needle moved before you noticed it. If the needle does not move at all, it means the hygrometer is broken. If you purchased your humidor at Neptune Cigars, we will replace it according to the terms of our Return Policy.
Tip: Remember To Always Check the Calibration of your Hygrometer: