Hi Dani,
My husband had an exposed bone area that caused him a great deal of pain. He was on various pain medications. Nothing was helping. He was on oral antibiotics for a few weeks also. I then read somewhere about antibiotic therapy intravenously. We requested for my husband to be put on this for a period of 6 weeks. Well it worked. He hasn't experienced any more pain.
I don't know if this is what your mother is going through. The doctors did not believe this would work but it did. It turned out that the pain was caused by infection that oral antibiotics were just not strong enough for. I hope this helps.
Maribeth