I started getting a callous on the tip of my index finger soon after I started playing disc golf. Lately, it has migrated to the side a little, as I've been throwing more putters, or maybe I just changed my grip a little. This past summer, I had a couple more along my index finger, but those have diminished as I'm not throwing as much DX plastic, it seems. There's something about the way an Eagle fits in my hand that causes a callous at the base of my index finger, but it seems to only develop when I'm throwing a lot of base plastic. Lately, I've been using Star Eagles more than DX, and the callous isn't as bad as it used to be. Or it may be that I'm throwing putters and mids more, I'm not sure.