Charlie, I found this article that I thought you might appreciate:
- Post Craniotomy Headache (2021) https://www.ncbi.nlm.nih.gov/books/NBK482297/

Pulling from the article, the researchers state: "Post-craniotomy headaches (PCH) are one of the most frequently encountered adverse events after craniotomy, presenting in over two-thirds of patients who have undergone the procedure. PCH falls under the category of secondary headaches and can present unique challenges in diagnosis and management."

The conclude:
"In the chronic phase, a shift to more non-pharmacological adjuncts may be considered. Alternatives to consider are physical therapy, acupuncture, TENS units, hot or cold packs, massage, or bio-behavioral interventions."

Have you tried any of these non-medicine approaches? Did anything help?