Mike Deeringer – AdSense Publisher Support in the official Google AdSense blog says the folks at Google appreciate the endeavors made by AdSense users in monitoring their accounts and keeping it in ship shape. Hence, they say, "However, we do understand that an accidental click may occur from time to time, so there's no need to contact us each instance this occurs."
Deeringer adds, "Because we closely monitor all account activity using engineering systems and thorough human analysis, chances are we've already detected your clicks on your ads and discounted them. While these clicks still show in your reports, we filter out their associated earnings so that advertisers aren't charged. However, please keep in mind that we don't ignore the clicks completely; if it appears to us that a publisher has been clicking on his own ads to inflate his earnings or an advertiser's costs, we may disable the account to protect our advertisers' interests."
Instead of clicking on your ad tool for a sneak peek, the people at Google suggest using instead the AdSense Preview Tool.