We have figured out that Rambo has a skin condition called, "Dippity Pig." I was reading in: The Complete Guide for the Care and Training of Pet Potbellied Pigs, and it said:
""Dippity Pig" is the name that has been given to a commonly occurring skin condition in pet potbellied pigs. A symptom of oozing sores, that may or may not be bloody, appear on the pig's back, neck or rump at the level of the spinal cord. This may be accompanied by severe pain that causes the pig to scream. In addition, your pig may or may not have trouble walking with its back legs. Often it drops its back end, drags its back legs and may even appear paralyzed before standing, taking a few steps and falling again."
-The Complete Guide of the Care and Training of Pet Potbellied Pigs
That is exactly what Rambo has, although he didn't really scream, he just squealed a little. We were so relieved to figure out what he had! It said to give him some Benadryl. So we gave him some, but he kept spitting out the tablet. So, we wrapped it up in some bread with peanut butter on it, and he ate that right away! I felt so for bad him! I hope Rambo feels better soon!