It should come as no surprise that “freeze branding” has become popular in a world where individuals are using Sharpies to trace their lips and applying haemorrhoid ointment beneath their eyes. But this is a leap even for TikTok’s standards.

Freeze branding, similar to the technique used on animals, is becoming more popular as a do-it-yourself body art trend. It entails applying a metal form that has been cryogenically cooled—often immersed in liquid nitrogen—directly to exposed skin. The cold kills hair follicles and pigment cells, creating a permanent scar that resembles a tattoo. It is intended to serve as a permanent ID for animals. It’s an identity issue in humans.

“Friendly reminder, you are not a horse,” said Dr. Andrea Suarez, a Houston-based dermatologist who’s watched this trend unfold from behind her fingers. In a video shared with her nearly 600,000 TikTok followers, Suarez explains how even a few seconds of exposure can lead to a full-thickness burn and a deep bacterial infection known as cellulitis.

Don’t Freeze Brand Yourself—Seriously

We’re talking about more than a little redness and swelling. The National Library of Medicine states that if left untreated, cellulitis can progress to sepsis, inflammation of the bones, or infection of the heart lining. Suarez pointed out that none of those factors make this safe, but that issues vary depending on the branding iron’s temperature, duration on the skin, and application location.

“After six weeks of intensive wound care, this is what you might be left with,” Suarez said, pointing to the raw, inflamed skin of one freeze branding enthusiast who lasted just ten seconds under the iron.

This is not a singular instance of a careless tendency. Freeze branding is another internet-based do-it-yourself remedy that doctors are urging patients to avoid. Regarding the Sharpie lip-liner craze, dermatologists have already voiced their concerns, cautioning that the marker ink near the mouth may release toxins into the blood. The same is true of haemorrhoid cream, an odd beauty trick that can cause glaucoma under the eyes.

Freeze branding may leave a crisp white mark that trends for about a week, but it also invites infections, scarring, and possibly a trip to the ER. As Suarez put it plainly: “Don’t do this.” Please. Don’t.