normal head

I have a very strange disease, and I seem to be the only one who realizes it. Looking in the mirror, my head turned into a paper bag.
It's not that I put a paper bag over my head on purpose for the sake of spoofing, but my head actually turned into a paper bag, and when I tried to remove the paper bag, it was like a matryoshka, one paper bag after another, In the end, there was a "pop" sound, leaving an empty neck.
I was a little frightened, so I ran to the hospital immediately to ask the doctor to take a look at it, because I was afraid of being caught as a monster, and I even wrapped a large black scarf around my head when I went out.
The doctor took off my black scarf one by one, then frowned: "What's wrong with your head?"
I was surprised: "Doctor, my head has turned into a paper bag, isn't it a big problem?"
The doctor's expression became a little angry: "You shouldn't waste medical resources to mock me, this is clearly a normal head."
"What? What's normal? Would a normal head be a paper bag?"
The doctor didn't seem to hear me, stood up and tried to drive me away.
I couldn't believe it, and put my head close to his eyes: "Take a good look? What does my head look like!"
The doctor said: "Your head is a normal head with a well-proportioned shape and no wounds. If you do this again, I will call the psychiatrist."
"What should a normal head look like?" I insisted.
"A normal head is of course what a normal head looks like."
I was a little discouraged and wanted to find a mirror to take a good look at myself, when another person came running.
"Doctor! My head has turned into a pumpkin!"
The man held his bald head in front of the doctor.
"But isn't your head normal?" I blurted out.
The bald man opened his eyes wide in horror, pointed at his head and said to me, "Can't you see such a big pumpkin?!"
The doctor picked up the pager and said, "Either you guys leave now, or I'll call the psychiatrist right away."
The man and I fled.
On the way, I asked him, "Do you think my head is a paper bag?"
He also looked at me strangely: "You are obviously a normal head."
We stopped in front of the mirror at the door of the bathroom. I was still a paper bag in the mirror, and he was still a normal head in the mirror, but he said, "Look, it's obviously turned into a pumpkin."
I think, maybe we have never really seen the world as it really is, but it is just what the brain wants me to see. You can't tell whether you are normal or abnormal, or that the standard of normal and abnormal is determined by What to formulate?
I said goodbye to him and walked out of the hospital gate. Looking up, everyone's heads turned into paper bags.