Before each profile update operation, a snapshot of all current data is created. To access the history of changes for a profile, click 'Edit' while viewing the Account Profile, then click 'History' in the upper right-hand corner

Clicking on a history entry will allow you to view the profile as it was at that point in time. 

Data that differs from the current value will be highlighted in orange in this view. You can hover over the orange icons to view what the current value is in the profile.

When viewing a previous profile version, click the 'Rollback' button if you would like to revert the profile to this version permanently.