What happens after a puppy eats insulation?

My 14 week old Labrador ate some insulation - I was wondering what could happen after she ingested it. She was fine when she was put in the crate for the night, but when she woke up this morning she couldn't even stand. She mysteriously has a sore leg that she can't walk on just 24 hours later ( she never injured it...) & is very weak and lethargic. I just returned from the vet & he gave her pain meds and said she must have injured herself in someway (which is impossible, since she is supervised 24/7) . Could the insulation have done this to her? What else do you think it could be?