How do I get a bolt out??

[jim-bob]

Taking apart my 67 GMC as much as I can before taking it to the body shop.(very little experience)..removing front fender and inner fender (PS)..was removing the bolts holding the inner fender to the edge of outer fender..as you all know the square nuts are held in place with a retaining clip..I was using my impact when one just started spinning and bolt not coming out..It's at the top and very hard to see but I can feel the clip has come loose from fender edge and distorted..I didn't use the impact anymore but did the same thing with another one using my ratchet..I cannot get a wrench or pliers in there to hold the messed up clip and nut..what can I do?? Please and thank you..