User blog comment:Gary299/High School DxD BorN episode 4 review/@comment-3965848-20150427051048/@comment-26209278-20150427074930

It's not a full heal, it's just a weaker version of Asia's ability. That's why we still see scars, and he still has pain (although not sure how he was fully healed the first time). Even Asia's healing would prove not enough for this damage, since it went fully through organ and tissue. Phoenix tears and Asia's Twilight Healing is what is needed for him (unless the anime think Asia's training is enough to heal this damage)