Hi @Zach,
If you are working in the VEC - there is an undo button. Or you just don't save when you changed something, then it's back to the way it was before. Unfortunately there is no proper versioning system in Target itself.
However, it is possible to run a cronjob via the API, which archives activities accordingly and which can be restored, e.g. if an activity is deleted by mistake etc., but this does not come out of the box. You have to write it yourself.