Postherpedic Neuralgia

My father is suffering from postherpetic neuralgia caused by shingles. He currently takes L-Lysine and L-ascorbic acid. But the pain is intense once the supplements are out of his system. He uses a "relaxing" essential oil blend that alleviates the pain. Is there anything he can do to make the pain go completely away? The pain has been unbearable and I hate to see him suffer. Is the pain permanent? Tweet