I was just playing around with my first 4x5 camera, hoping to start shooting with LF photography for the first time in the next few days. However, as I was examining the lens, the aperture became stuck! About half of the blades no longer move properly when adjusting the f-stop. In addition, there looks like there is a fair amount of torsion on a few of these stuck blades, and it has caused them to leave what appears to be little grease marks on the inside of the lens. It seemed adjusting the stops for the pictures I've attached seemed to make it worse, so I'm rather afraid to adjust it any more than necessary.
Is there anything I can do to fix the lens? I don't really have the money to put into buying another lens at the moment.