Suggest Remedies For Swelling And Tenderness In Finger Tip

my index finger on my right hand has swelled up and is now over double the size of the one on my left hand, i an unable to straighten the finger and the skin beside the nail has now started to go green. The full fingertip is tender and i am unable to touch anything with it. The finger nail has now started to lift fron the finger an is becoing dry and chalky.