Oh my goodness, I am so sorry to hear about little Panzer. Please do not blame yourself. There was absolutely no way you could predict something like this would happen. I hope he poops soon and continues to improve as swelling goes down.
Acupuncture and laser therapy should be very helpful, especially if you have a very skilled acupuncture vet.
Rafi, the german malaroo, age 9.5ish http://www.dogster.com/dogs/693238
Varda & Gio (the crazy cattens)
Warming my heart: