PEEK is polyether ether ketone. It's a heavy duty plastic they use for bone replacements and a million other things. It's what they would probably use to create an artificial bone flap if they could not use the original. It's supposed to be better than titanium because it does not leak any minerals the way some metals can, it's not prone to infection and you don't get any expanding or contracting when it gets hotter or colder. It also does not interfere with MRIs or any kind of metal detector because it's not metal or magnetic. The downside is that it only lasts about 100 years, so if they vastly expand the human lifespan in the next few decades, I might need a replacement. But if the money men keep hold of the medical industiry, I'll be dead long before it expires.
Just like titanium, you can feel my plates. I must have spent at least a month just touching my head. What surprised me the most, and always surprises civilians, is how small they are. When I was first told what they did to me, I expected one giant metal patch in my head like in war movies, instead of a few tiny bumps. Everyone is always surprised that the skull they cut away was put back. When you know the procedure, it makes perfect sense. But when you know nothing about a craniotomy, it's easy to assume that they throw the bone flap away.
I'm not surprised about the headaches. Everyone I've talked to says the same thing. The good news for me is that I live in China. I can get a bag full of prescription drugs for $5. It doesn't make any difference what the drug is, it's always $5.