Not in the area of the valves. Only a plastic wedge at the left front corner, and very carefully.
I'm not losing a great deal of sleep over this. It's fixed, and whatever I did was obviously because I wasn't paying the proper attention to what I was doing. I've pulled heads off blocks dozens of times and never had this issue. While it would be nice to know how it happened, I'm just going to chalk this up to experience and move on - more carefully!
