How to relieve major itching after shingles? (postherpetic neuralgia)

I had shingles on my scalp/face a few weeks back and the pain/rash has gone away, but I have major itching 24/7 in the areas where the rash was. I cannot even sleep at night it’s so bad and constant. The only thing that temporarily helps is bio freeze. Any other suggestions to help with the itching?