Yesterday, I Suddenly Felt Pain (to The Touch And When

Yesterday, I suddenly felt pain (to the touch and when making a fist), along with redness, on my right hand, finger next to the ring finger. It's not swollen, and it's not bright red, but when I try to make a fist, the skin seems tight. I don't recall hitting it on anything, so I'm not sure what the heck is going on. I have arthritis in my right-hand index finger, but this latest deal doesn't look anything like, nor feel, similar. The arthritic joint is larger than the other knuckles on either hand, but that's not the case with the knuckle on my left hand.