It looks like the skin is inflamed. Does it itch? Have you had skin scrapings and exams? Have you tried changing your hair care products.
When I eat even a trace of gluten I get itchy bumps and rough areas on my scalp and in the hair on my neck. This can last for as long as the immune system is producing auto antibodies - three months or more. I had this before I stopped using gluten and now the reaction occurs only after gluten ingestion.
The only hair cleanser I use is a saturated solution of Borax followed by a citric acid rinse.