Then I saw it. There, in the drawer, next to a can of deodorant and a box of expired condoms: a packet of interdental brushes. Little brushes with bristled heads, each brush about the size of a pin. The dentist gave me them a couple of years ago. She'd said I needed them. I haven't used them.

I took out one of the brushes. I stuck it in between two front teeth and brushed back and forth. I did the same for all the other teeth. It seemed to make my teeth even cleaner.

There was only one place left. The very back of my mouth, the space behind one of the molars. I couldn't see properly so I turned the torch on my phone and shone the torch in my mouth. Now I could see. Soft pink tissue. I felt like a dentist performing a procedure.

I tried to push the interdental brush behind my back molar. The brush wouldn't go in. It kept hitting the tooth and bending.

"Get in there, damn you!" I said.

The brush still wouldn't go in. I jammed the brush in there with the tenacity of a man trying to shove a fat cat up a drainpipe. The brush entered violently. I felt a curious mix of pain and pleasure. I knew immediately I had found the source of my pain. I pulled the brush back and forth in a rough sawing motion.

It felt odd, cleaning there. It was a part of my mouth I had never cleaned before. It was like accessing a new zone in a video game.

I pulled out the brush. I could taste blood in my mouth. There was blood on the brush. There was also a tiny sickly yellow blob on the brush that might have been food or bacteria. I washed the brush under the tap. My teeth felt better. I used the mirror to look inside my mouth. The pink gums were stained red with blood. Blood because I had never flossed there before.

So I guess I might have solved my toothache.

My head still hurts though, from where I had a hair transplant.