I’ve got something similar at the moment, ring finger on my right hand has been hurting for weeks. I don’t know for sure that it’s biking-related though. I’m very careful not to grip the bars tightly (learned that discipline in my archery days).
Where the pain is, if I was to press on the lowest fleshy bit of my finger (nearest point to the hand without it being hand), and counteract that with pressure on the back of the first knuckle just above it, it hurts like a mofo. Day-to-day, it’s fine.
No clue what’s wrong with it, but it’s been like that for weeks.