10 Month Old Opossum

I have a non-release male, that up until yesterday had been thriving and healthy. We stick to a solid diet, he's always been very active and happy. Yesterday morning I noticed he had barley eaten his food and when I entered his outdoor enclosure I noticed he had a limp. His back left foot or possibily leg seemed to be causing him pain. He's still drinking water, he ate a few bites of food last night but all he woukd eat was a few bites of fish and some mozzarella cheese. He didn't touch anything else. Thus morning I went to check on him and he is worse. Yesterday he was at least lifting himself up with the 3 other legs and walking and occasionally trying to put weight on his back foot. But now he is more like crawling than walking. He seems so sad, I don't know what to do. Does anyone have any suggestions on what we can do or try? He doesn't show any other of the usual signs of MBD, NO ticks or hunched back. Last week we did have an issue with a wild opossum bothering him from outside of his enclosure so I don't know if maybe he somehow got hurt when that happened but didn't show signs until now? I'm a complete loss on what's going on with him. He was up running around and climbing, eating and doing great just days ago it's so sudden and seems like it's all so fast. In the part of Florida i live, most rescues in my area are small independent people and so unfortunately I don't have a lot of options for veterinary care. I would even be open to letting a larger or more equipped rehabber take him if it meant he might get more help than I can offer him right now. I hate to see him unwell 😫