I have a red spot on the back of my right hand - size of a half dollar.  There is pain in the back of the hand as well.this started 2 weeks ago on my left hand - went to emergency room & was diagnosed with infection and arthritis.  Now its on my right hand.
Consult physician for physical examination, he may recommend blood test for hologram, esr, crp, anti-ccp to rule out rheumatoid arthritis. Can take ibuprofen & apply gel topically for pain. Take care.