I shoot 3 under and lately I've been developing an irritating callous on my ring finger.  What does this say about my technique.

hey same here but i shoot split .ive been playing around with different release and notice if i get a deeper hook on the string its not as bad but still there so im interested to see what everyone says.

I think a small callous can be normal but often it is a sign that you have your elbow too high.

Mark

You could be torquing the string...your string hand is not inline with the string...this is very common and results in a callous on your ring finger.  

When you draw the bow to anchor, instead of the string being in the same plane, your have induced a kink with your string hand.

How do I fix that?

Make sure your fingers are inline with the same plane as the string, and don't twist your wrist outward when you draw the bow.

Use the Fischer release/grip.

I had a problem similar and got some great advice after a lot of searching for the problem. The problem was the ring finger was not releasing at the precise same time as the others. I ended up taping the ring finger to the middle finger between the first and second joint. I also started using a second anchor point which is my ring finger on my chin to prevent torquing the string.

Ditto what Terry said, or atleast that's what caused it for me when I fought it.

Started paying attention to the angle of my hand in relation to the cant of the bow.  I also started to pick up the string with my middle finger first liks Dale Karch does in Masters of the Barebow.  Together they seem to have fixed the problem.  I don't know how I started to do that.  Never a problem until the last couple of weeks.  Thanks for the help.