Do you stand the chance of getting banned from google adsense, even if accidentally you click only one ad. on your site.
Clicking once won't get you banned...or paid. Google accounts for the "acidental click". Follow the TOS (don't click your own ads...anymore) and you'll be fine.
Google knows that people may accidentally click on their own ads, and won't ban you for doing it once. You can email them and just let them know you clicked by accident, if you are really worried. Just try to be careful and not click again.