I Have Itching On Back, Scalp [ Side Only ]

i have itching on back, scalp [ side only ] eyebrow the itching is terrible sometimes, so bad that i have scratched till i have left sores. this is all on left side. I went to a dermatologist, she said she thought it is a nerve. Is there anyway to find this nerve and stop this terrible
itching? I have been using 2 different types of dry skin cream and gel. Geri-Hydrolac and bikini zone
gel. Both help some for a little while. Help!!!! i am miserable. Thanks Vikki