Hiding the bend lines also hides the sheet metal bend notes.
Solidworks sheet metal drawing show bend lines.
No bend lines but bend notes are show then your sketches are more than likely not set to view.
Displaying solidworks bend lines the first method i tried was to go to view sketches.
No bend lines or bend notes are show then your bend line sketch for that view is more than likely not set to show.
To unmerge bend notes right click the merged note and click unmerge bend notes.
Expand the flat pattern feature right click bend lines and select show or hide.
Search toggling the visibility of bend lines in the solidworks knowledge base.
This toggles the visibility of sketches and if it is off the bend lines sketch will be hidden the second method i used was to expand out the flat pattern in the feature tree and find the sketch bend lines2 could be other numbers shown.
In the drawing view propertymanager you can.
Show or hide bend notes.