How can I determine the changes I've made to my ISPF Edit data before I save it?

I've been editing and testing JCL for sometime without doing a save under ISPF Edit. I changed something and the JCL now fails (JCL Error). I know I can look in the jobs sysout using SDSF but is there a way to find out what I changed while in ISPF Edit?

For #2 - Or if you avoid PDSE's like I do, the CBT Tape PDS command has the RESTORE function where you can often find the previous member.