Is there anything I can do to treat the neuropathic pain I've developed after my syringomyelia surgery?

Maybe. Sorry to hear this. These things may take some time: r lipoic acid 100 mg 2x/ day, b vitamins (be careful not to take too much b6). Good nutrition is key; probiotics can help nutrient absorption try acupuncture (may need to try several practitioners) and find someone with a therapy called frequency specific microcurrent. My clinical experience with these indicate they work for some people.
Yes. There are medications to suppress your symptoms, although there might be no complete pain relief. I would suggest discussing with comprehensive pain clinic specialist.