Are there feats to help you cast a spell AFTER you have taken damage? Not defensive casting.
Uncanny Concentration gives you a +2 to all concentration checks, but the prerequisite seems generally useless for what you're specifically trying to accomplish.
Raging Concentration gives you a significant bonus to your concentration checks, but only while you're in a bloodrage (and thus are a bloodrager).
Otherwise, benefits typically only help if you are defensively casting.