Rollback without tag in changeset

We are using the git flow model for our development and trying to integrate liquibase for managing the database versioning efficiently. The problem comes when a developer is working on a feature branch and has made a DB script which is executed on his database and another developer’s database, but it is not yet part of any release so it is not yet tagged. Now that feature is tested and becomes part of release and we tag the changeset and execute it on production.

The questions is how to rollback the changes made on the developer’s machine because there was no tag defined at the moment when the script got executed and when we try to update it will the current tag it will show error “The table already exists”.

How to manage these conditions through liquibase efficiently ?