The ONLY way that a purge can be reversed is if the lower court makes a finding of contempt, ordering a purge and then the Appeals court rules that the findings/order is reversed. Basically, that virtually never happens.
So, a purge, in and of itself, cannot be reversed, but it can be disharged simply by paying the purge amount. It will still show as contempt in the file, but it will be noted that the purge was paid and discharged.