Hold the Shift key and left-click on the skull ornament to toggle its visibility.
This mod uses extended hair physics and therefore it requires Loader v5.45 or greater. If you are unable to use the Loader, or if you find that the hairstyle misbehaves in conjunction with advanced Animtools positions, then you may have more success with the Static version.
Normal users can download the MOD file via the link at the top of this page. SDT modders can find the FLA source file on mega.nz.