The Top of my Head is Severely Itchy After Almost 3 Months Since I Had Brain Surgery, How Do I Get the Itchiness to Stop?

I had surgery at the beginning of February to test Deep Brain Stimulation (DBS) for depression. DBS has been used for a long time for Parkinson's patients. Ever since surgery, the top of my head has been itching severely to the point that nothing takes away the itch. I've scratched to the point that it has bled and it will still itch. I tried switching to organic shampoo and conditioners. Then I tried organic shampoo and conditioner that is supposed to normalize scalp conditions. Now what?