The first time I acknowledged to myself that I loved you, a patch of my skin blistered and died. The remnant was rough to the touch, the dull crimson of poison ivy, and crinkled like a first-degree burn. It was on my left arm near the elbow.

It’s funny in retrospect how little I minded. The disease seemed innocuous at first. I thought it would clear up in time. Thousands before me have told themselves the exact same lie.

We met up for a drink with our mutual friends. I sweated through the jacket that covered the scabs on my arm and talked to you in words I barely understood. Your replies were sound and motion; my senses, trying to follow them, spilled like alcohol across the table and dripped onto the floor. Under the hot blue light your eyes were large as a ghost’s and shining.

The next morning when I woke, I found that it had spread. The rough patch by my elbow had more than doubled in size, creeping down towards my hand and upwards to my shoulder. It was harder now, and a darker red, the colour of liver. When I tried to bend my arm, the joint resisted. I was starting to calcify.

I booted up my computer and scrolled through encyclopaedias of different ways to die.

Then I bit the bullet of my lower lip and dialled. Not in at the moment; please leave your message after the beep. I hung up.

Later the scab on my arm cracked and began to weep a pale, viscous fluid that clung to my fingers like oil. I covered it with a bandage, but the infected skin crawled until I couldn’t sleep. At last I got up and switched on the light. The bandage was damp and smelled hotly of decay, and the disease had grown far beyond it, covering the whole arm and half of my chest. My sheets were slimy with white secretion, littered with a patina of hairs shed by the dying flesh.

I booked an appointment with my GP. Urgent. On the pristine surface of the doctor’s desk, my fingers looked brittle enough to snap. She inspected my arms with a microscope, ran her gloved hands across my ridged red ugliness. Perplexity pressed its thumb between her eyes. ‘I can’t see anything wrong,’ she said.

Nor could the skin specialist she referred me to. In his mint-green consulting room I heard the word hypochondria for the first time.

‘What’s the matter with you?’ I said.

‘I look like something out of an eighties B-movie!’ I said.

I looked into his eyes and said, ‘Please.’

‘I’m terribly sorry.’ His politeness, shallow as the puddles on a bathroom floor. ‘I wish there was something I could do.’

I went home and opened my medicine cabinet. Sudocrem lay uselessly on the surface of the skin for hours, unabsorbed, until I wiped it off. Aloe vera stung like cold fire but did nothing. Vaseline was a waste of time.

I took pills. Benadryl, bicoloured antihistamines and the tiny white moons of hydrocortisone tablets, which you could snap in half to speed up their effect. I took them one after the other and lay on my bed and made paper aeroplanes out of the brochures the doctors had given me. The title of every leaflet was prefixed with psycho. I supposed I ought to be grateful. A hundred years back, they would probably have dissected me and put me in a jar.

Ethanol.

Formaldehyde.

Glutaraldehyde.

Phenol.

All those elixirs of death with their pretty little names.

It’s funny, but I’ve never mentioned love to you. Our relationship is built on small things, in-jokes and song lyrics and moments snatched from our separate lives, tiny specimens in dozens of jars. Love isn’t life, but it fills the spaces in between.

I called you again, and this time I left a message. Then I went downstairs and made myself a shot. I can’t remember what it was; some kind of schnapps that smelled like cinnamon. That didn’t matter. It was time to look.

The mirror I had hitherto ignored was framed on three sides by wall, its bottommost edge perched above a sill that grew bottles of beauty products like toadstools. But when I gazed into its silvered heart I saw I hadn’t changed. I was a little paler than usual, my expression anxious and drawn, but my reflection showed no trace of the disease that was consuming me, inside and out.

I still held the shot glass in one mutilated hand. A cool trickle ran down the side of my face as I tilted my head back and poured it into my eye. The pain was almost unbearable, and through my tears I saw the room break apart into a thousand glittering facets. I filled the glass again.

The scales were creeping up my neck now, over my ears and chin; soon they would cover my face. I touched my blistered cheek. ‘Why can’t anyone see it?’ I whispered. I was miserably drunk. ‘For fuck’s sake, why can’t anyone see?’

The next morning you knocked on my door. Leaning against the doorframe, buckling under the weight of your gaze, I said nothing; watched you try and turn your wince into a smile. Relief like warm soapy water. Then you spoke.

‘What’ve you done to your eyes?’ you said. ‘They look really bad.’

I went to the kitchen and found a ball of steel wool lying in a Gordian knot on the draining board. Following, you found me kneeling on the floor, bubbles of fluid seeping from the cracked and darkening skin as I scoured my hands and face as if I could wash this cancer away.

You caught my wrist. ‘What’s happening? What are you doing?’

‘I don’t know,’ I said. ‘I don’t know.’