With the Mac OS X operating system, there is no Apple supported way of going back...in fact, once a new version has been released, the prior versions are no longer available from Apple.
The only way one can downgrade from 10.8.2 to 10.8.1 is to have a clean copy of 10.8.1 on another source such as an external hard drive, then erase the startup disk and install the prior version. Doing so removes everything on the internal startup disk so you must have a good, up-to-date backup of the material on that drive.
One way of doing this is to use software such as Carbon Copy Cloner to clone the hard drive to an external drive before you install the 10.8.2 update. That way, if you do not like the update you can erase the hard drive and clone the external drive back to the internal drive.
This is a lot of work with a lot of opportunities to make a mess of things so approach it with great caution.