When the gunfire slowed enough for laughter and hooting to become audible, I crawled out from under my bed, smoked several cigarettes, and went to sleep. The next morning, while brushing my teeth, I saw that my previously brown lip-bristles had lost all color from root to tip.

My canities subita cannot be medically authenticated, since no doctors were around to see it. Nevertheless, I reached out last week to Des Tobin, a leading expert on cell pigmentation and director of the Center for Skin Sciences at the University of Bradford. Over the phone from Ireland, Tobin patiently explains why my account is logically impossible: “There are no living cells in the hair. Psychosocial stress can’t affect the hair fiber that’s already formed, it can only affect the fibers as they’re forming.”

He suggests that what I thought was canities subita may have been an occurrence of alopecia areata, a stress-linked autoimmune reaction that causes sudden hair loss. Because it often targets pigmented hair while leaving de-pigmented strands in place, this form of alopecia is the leading explanation for the appearance of sudden hair-whitening in people with salt-and-pepper locks. The pepper falls out, the salt remains.

I interrupt that my mustache is as thick as it’s ever been. And it was sparse enough before the incident that I would have noticed any white hairs that were already there. For good measure, and to demonstrate the extent of my Googling on the matter, I add that I have also not experienced any skin-whitening vitiligo, which sometimes accompanies the sudden appearance of white hair.

Tobin next inquires about my genetic background, my age, and the condition of my mustache at the time of the blanching. I was 30 years old in October 2013, I tell him, and inherited my hirsute upper lip from the Iberians on my father’s side. A salon professional had last depilated said upper lip roughly one week prior to the event, meaning the hairs were wispy, but present.

At the mention of my salon routine, Tobin points out that depilation itself can make hair more susceptible to blanching, by inflicting “microtrauma” on the follicles and rendering them more porous. “In rat studies,” he offers, “they showed if you pluck the rats’ whiskers, they grow white more quickly.”

For my whiskers to whiten all at once, Tobin says I would have had to be in direct contact with some external agent—a detergent used on the hotel’s sheets, perhaps. My years of upper-lip microtrauma and the resulting porosity of those follicles would make them more susceptible to being bleached, and would explain why no other hairs were affected.

If so, the stumper remains that the hairs are still white, nearly three years after the fact. “Whatever has happened managed to affect the melanocytes inside the root of the follicle, and caused them to shut down completely,” Tobin muses, referring to the skin’s pigment-producing cells. I offer to mail him some clippings from my mustache so he can analyze the hair shafts for himself. He politely declines and our phone-consult ends there.