HI - beautiful pan cel by the way. Haven't seen 
the show - but I know that larva is *very* hard 
to come by apparently... ^_^

About damaged bg's. I heard that they um... roll 
the oversized/pan cels and bg at the studio. 
*correct me if i'm wrong dealers...*

Also - what I believe the bg's are painted with 
is gouache. Gouache does crack - and if/when it's 
rolled or handled a lot - cannot take the abuse. 
Notice that dark/black bg's can be "scratched" 
easily? 

I think that heavily damaged bg's are eventually 
discarded as well - so you are very lucky to even 
have it! I think the effect just wouldn't be the 
same without that bg. ^_^