Actual blisters, or callous? If you didn't have them before swapping to the larger diameter grips, that is likely your answer assuming nothing else has changed. Go back to thinner grips.

I build up some wicked thick callouses at the bases of my fingers, particularly the last three. Doesn't matter what glove/grip combo. Keep 'em trimmed, no big deal. Don't think I've ever had any sort of blisters.