Ischemia after Hair Transplant
The first concern is having a hair transplant done by an unlicensed individual and not the doctor. Patients need to do more research before they decide to go through with this procedure. I have not encountered yet a purplish band around the forehead however this could be bruising and generally will go away with time. It could be due to the recipient sites being created too big or too deep or a combination of both. Without photo's it is difficult to tell however this is not normal 10 days after a hair transplant. I would recommend reporting the physician to the ISHRS for allowing an unlicensed individual perform surgery on you.
It seems you lost your trust in your doctor. If you believe something went wrong and you want a second opinion, you need to see a doctor in person so the doctor can examine you.
Get a second opinion ASAP. You need an expert to tell you what is happening to your head if your doctor will not tell you.
Pigmentation after hair transplantation
Without photos it's difficult to tell. But from what you describe I would say you have postinflammatory hyperpigmentation. The doctor is correct in stating that the hemosiderin or iron pigment from blood seeps into the surrounding tissues and causes that discoloration that you're describing. If you are darker complected this is more likely to happen. At one month you are still very early in the postop healing process. It often takes 3 to 6 months for the pigmentation to resolve. As far as the technician placing grafts versus the doctor, this is the standard of care in most hair transplant practices around the world.