Ouch, that looks nasty.
I bounced my Epi SG a while back (from playing position, neck went straight down and hit the arm of the sofa - drop of a foot and half mebbe - don't ask what I was doing :roll:)
That produced a crack in the finish that I'm sure wasn't there before. But everything seems stable and has for weeks. I decided that if anything funny starts that I'd be venturing down to Jonathan at Feline - but I'd completely forgotten about it, so obviously nothing untoward has shown up since...
Yours "looks" worse though, I would be inclined to want a qualified opinion if mine looked like that...
EDIT: "don't ask what I was doing" - that'll be red rag to a bull - OK, I was @rsing about, thinking Angus Young in the living room, without my homemade straplocks on...