I have been getting these sores on and inbetween my fingers.  They start out itching, then unknowly I start to scratch them forming into blisters.  They eventually pop and turn into sores until eventually they go away.  Then it starts all over again.  I don't know what causes them but they don't look nice.  I try to hide my hands because it seems embarassing.  Mostly, these sores appear on my right fingers and then a lessor amount on my left fingers.  I also have noticed when I extend my fingers, the one next to my pinky is bent.  I have to use more force to straighten them out.  There is also a larger sore on that finger.  Could it be a form of an auto-immune disease as I do have fibromyalgia and my blood test showed that my rheumatoid factor is elevated.