Constant numbness and burning pain in face and mouth.

Desperate to help my mother who's suffering.It all started in April 2005,first symptom was like a cold sore near her mouth that wouldn't go away for over a month.Viral medications didn't work, she tried cortizone cream and eventually went away. next symptom was a lesion on one finger,looked like a hole, there was no pain,just wouldn't heal.almost two months to heal.So far didn't seem serious.Then she was stung 5 times by wasps, 3 on one hand and 2 on the other.Coincidence or not..the following morning she woke up with extreme numbness and pain in her hands and was diagnosed shortly after with carpal tunnel in both.Also,at that time, her fingers and toes started going numb, turning white then blue.Then,almost immediately after carpal tunnel surgery,her cheeks started tingling with numbness.It gradually got worse and spread to her nose and mouth. She went to her GP and he diagnosed her with Rhuematoid Arthritus and secondary Raynaud's.He referred her to a Rhuematologist.The official diagnosis:Mixed Connective Tissue disease. Prescribed on several different meds, nothing worked for facial symtoms (symptoms), which was getting worse,painful to touch,hurts to wear glasses,trouble eating and talking, especially in evening,due to numbness and burning.Went to a neurologist,did an eeg,mri of head and muscle biopsy,all normal.She's now seeing an Oncologist,with background in Rheumatology who's putting her through chemotherapy? 4 sessions, she's been through 2, can't continue due to low white blood cell ct. Does this treatment make sense? And so far not working.Please,any advice is appreciated.

[CCF-Neuro-M.D.-SH]

First of all, keep in mind that I am unable to diagnose you because I am unable to examine you, this forum is for educational purposes.
   Secondary Raynaud's can be difficult to treat.  I assume the "chemotherapy" that she is getting is for her underlying rheumatoid arthritis/mixed connective tissue disorder.  Agents such as methotrexate etc can be helpful for the underlying condition, but does not improve the Raynaud's.  Medications that have been shown to be helpful include nifedipine, amlodipine, prazosin, and doxazosin.  These are agents used for blood pressure control, but are also useful for Raynaud's because they relax smooth muscle.  other atypical agents have also been reported to be helpful including prozac in some refractory cases.  Another therapy that can be helpful is rubbing Nitro paste to the area that is affected.  This relaxes the blood vessels in this area and prevents the Raynaud's from cutting off the blood supply.  When severe damage occurs (non-healing ulcers) surgery is sometimes needed to remove nerves etc from the blood vessels.
I hope this has been helpful.