I was working at a job that required the frequent use of exacto knives and from time to time people would cut themselves through improper use of the instrument. Most of the cuts were small but the odd time someone would really gash themselves open and require stitches. The worst cut I ever received was not on my hand but on my ankle. I was cutting a box on the floor and was slitting quickly and aggressively. The blade slipped out of the cutting groove in the cardboard and hacked my ankle. Blood was splashed everywhere and I ended up getting fifteen stitches.
Then one day at work I was cutting a box of thick rugged cardboard with a dull blade. I had my non cutting hand on the box to hold it steady and started the cut but the knife got jammed and I should have stopped and put in a new blade, but I didn't. I kept pulling on the knife and it flung to the side slashing my thumb.
I paused for a second knowing that I might have cut myself very badly and didn't want to look at my thumb. Finally I turned my thumb over and it seemed normal. But a second later the razor sharp cut which wasn't noticeable at first opened up and the blood started to flow. I watched the blood drain from my thumb for at least a minute until it was soaking my sleeve. For whatever reason I froze and became fixated on my thumb. The cut thumb grew larger and larger in my mind. Before I knew it all I could see was the bleeding thumb in my focal awareness which appeared a hundred times it's normal size.
My mind had become obsessed with the image of the bleeding thumb and had magnified it to the point where I couldn't see past it. The image was imprinted into my mind. A couple of co-workers came to my assistance and I told them for what ever reason I could not see, but I did not tell them about the image of the thumb in my head.
I walked with them to the first aid room. I closed my eyes and even with my eyes closed all I could see on my mind's mental screen was the God damned thumb. The more I wanted to get rid of the image the more persistent it became. When I opened my eyes the image of the thumb was still there, blocking my view of everything.
I sat down in the first aid room to get fixed up, hoping something would take my mind off the thumb. As I sat there I did everything in my power to not look at my thumb. I was slowly losing control of my faculties so I titled my head up and stared at the ceiling lights. After a minute I turned away hoping I would lose the image of the thumb, but I didn't as the thumb reappeared as an after image of looking at the lights.
I got up unable to see anything but the thumb and I walked into a pallet in the backroom and sliced my big toe on a nail sticking out. I pulled off my shoe and sock to have a look at my big toe.
It was cut bad. But at least I had got rid of the image of the bleeding thumb out of my head because it was now replaced with the image of my bleeding toe.