If you cannot see changes that have been made to a form template, then it's possible that you saved the draft, but didn't deploy / publish the template.
If the form you're looking at was created before the template was saved of published, then the changes will not appear there either.
Form changes will only be visible on new forms that are created/started from the template after the changes that you have made have been Saved and then Deployed / Published Template. They will not retroactively appear on any forms that were already started before the changes were made to the template.