To make minor changes in the Masking, make use of the Snapshot tool. Snapshots enable you to change the masking (Link to what is masking) on a project while keeping the original masking version intact. You can save up to 10 Snapshots under each project in your account. Find the Snapshots (camera button) option under the “Visualize” tab.
Watch this short video about Snapshots and learn how you can best take advantage of this helpful feature