Wow - 4,000 rounds in a month, huh? And I thought I was bad...
I have no idea what to do about your trigger finger. For me, it's always my middle finger that takes the abuse. It's the one that gets smacked by the back of the trigger guard on revolvers and traditional rifle (bolt action, lever action, single shot) designs. I've actually developed quite a callous on the first knuckle on that finger, having actually split it open on far too many occasions when shooting heavy magnum revolver and rifle hunting loads.
I'm glad you are enjoying your new hobby. Like you have mentioned, it can become quite addicting.