I Am A 39 Yr Old Female And About A

I am a 39 yr old female and about a week ago I was siting down and a gradual started in my right index finger from the joint at the base of my finger to the middle joint but no pain to the tip of my finger. It doesn't hurt on the back of mine hand when I press the joint but when mi hand is palm up and I touch the joint it hurts. I can't grip the top on my tea or water bottle to open it. What could be the problem? I am a type 1 diabetic on a pump.