Frank Ahrens was director of global p.r. for Hyundai, based out of their Seoul, South Korea, headquarters. One day, his employee Eduardo gave him shocking news.

“Sir, I got a hair transplant!”

Eduardo, in his mid-20s, had “a full head of hair worn long enough to touch his collar and cover his ears and his forehead. If you looked at Eduardo’s head, there was no place you could think of to put more hair,” Ahrens writes.

As Eduardo proudly showed him the stitches from the transplant, which cost almost $3,000, an incredulous Ahrens asked why he did it.

Eduardo explained that he’d seen hair come out in the shower and thought he noticed his hairline begin to recede just slightly. He added that everyone he’d spoken to — from his team members at work to his parents, who paid for the procedure — agreed this was the right thing to do.

Welcome to South Korea.

In his new memoir, Ahrens, a former Washington Post journalist, tells of the three years he spent in Seoul working for Hyundai and his rough adjustment adapting to a culture that is, in many ways, the polar opposite of how we live in America.

When Ahrens’ wife, who worked for the Foreign Service, received a posting in Seoul, Ahrens was hired by Hyundai to head up their global p.r. effort. But almost two decades in a Washington, DC, newsroom hadn’t prepared him for his new home.

For one thing, Korea’s culture of personal improvement would make a Kardashian blush, as plastic surgery is far more pervasive than in the US. This obsession with appearance is known there as “lookism.”

“South Korean women use on average three times as many daily skin-care products as Western women,” Ahrens writes, noting that plastic surgery is so common, it’s regarded as a major economic engine.

“There is a medical-tourism booth in Incheon International Airport. Korea has the highest number of plastic surgeons per capita and the world’s highest rate of cosmetic surgery. Buses and subway ads all over Seoul show highly graphic, often gruesome before-and-after photos.”

While liposuction and breast augmentation are the most popular types of cosmetic surgeries in the US, Korean plastic surgery is most often centered on the face, with procedures on chins and eyelids (for making the eyes appear more Caucasian) among the most popular.

The motives for this go beyond narcissism, speaking instead to the intense competitiveness of Korean culture, where résumés include headshots, Ahrens writes.

“Job applicants know that in Korea, as everywhere in the world, the better-looking of two equally qualified job seekers will likely get the position,” he writes.

“So instead of being hypocritical, as Koreans would say Americans are by pretending looks don’t matter, Koreans understand the system and try to succeed within it . . . to not choose plastic surgery, if it will improve your employment and life prospects, would be considered . . . ill-advised.”

Appearance is so important to Koreans that many couples “rent strangers to be wedding guests — it’s an actual business — so their real guests will be impressed by the size of their weddings.”

As obsessed as Koreans are with appearance, they are equally driven, somewhat ironically, by alcohol (which rarely improves anyone’s looks once the booze wears off). After a hard day at the office, corporate Koreans are expected to socialize with their co-workers, drinking like frat boys with something to prove.

Ahrens, normally a two- or three-beer drinker at best, writes that he had “been warned and had read about the Korean drinking culture,” which is so omnipresent he was asked about his drinking in his first job interview with the company.

“I was asked, ‘Do you drink alcohol? Your team will want to show respect to you by giving you drinks.’ ” He mentioned that while he can “enjoy a good beer,” he was sure “there were other ways my team could demonstrate their respect.”

He was wrong.

Koreans, it turns out, drink “more alcohol than anyone on Earth.” One study found that the typical Korean “downed an average of 11 shots of alcohol per week.”

That’s more than double the average Russian, who comes in at No. 2 with a measly five.

Korea’s national drink is soju, “a clear alcohol, typically made from rice or barley,” with an alcohol content of about 20 percent and a government-mandated price of about $1 per bottle, “so all Koreans can afford their birthright; constant access to a momentary escape from their hard lives.”

Soju is considered more than just a drink in Korea; it’s a corporate bonding agent believed to lead to “closer teamwork, better productivity and the creation of real affection between colleagues.”

At one business dinner, a high-level executive made a toast. Raising his glass, he said, “Is this soju?”

“ ‘No,’ they shouted back.”

“ ‘Is this our spirit?’ ”

“ ‘Yes!’ they replied.”

This isn’t to say that Koreans are totally freewheeling. Ahrens was often stymied by Korean traditions of respect and unwittingly insulted or discomforted those around him.

Korea in general, and Korean corporate culture in particular, follows dictates of Confucianism, which leads to bosses calling employees by their first name but employees always referring to their bosses by title and last name.

Ahrens committed a cardinal sin against the culture when, at the start of his tenure, he told his employees, “Call me Frank.”

He later realized he had tried to “establish a Western workplace in an Eastern culture,” and caused all sorts of problems.

“ ‘Call me Frank’ made some of my team members uncomfortable and drained me of some of my rank and status,” Ahrens writes. “They didn’t want to call me Frank . . . it made them feel like they were working for someone of lesser status than all the other directors.”

Ahrens was constantly blindsided by Korean traditions. Normally a formal, suit-wearing environment, he was taken aback when he arrived at work one day to discover “every non-executive male employee was wearing a short-sleeve button-up shirt, in white or light blue, with no tie and no jacket.”

No one had said a word. The change occurred as if by osmosis or some sort of psychic communication. He later learned the company allowed cooler clothing in the summer but found the way it happened “disorienting,” as no word had been shared. Everyone — except for him — just knew.

Ahrens even made his employees uncomfortable while trying to praise them. Anytime he’d single one person out for a job well-done they were “mortified,” replying instead, “It was a team effort.”

“Boldly expressing individuality for the sake of it was not a sign of independence and accomplishment, as it was in the US,” he writes. “It was rude and inconsiderate to all those around you.”

Ahrens tried to bust through the culture, including throwing a party at his house with people from work and others. But his employees viewed it as an obligation. They spoke to no one there but their fellow co-workers, and spent the night serving drinks to their superiors.

When Ahrens asked his team leader about this, the reply was, “Sir, we don’t go to parties where we don’t know everyone.” Ahrens said that parties in America were often for meeting people but was told that Koreans “make their friends for life in school.”

“How do you make friends as an adult?” Ahrens asked.

“We don’t,” was the reply.

Ahrens got a taste of this extreme hierarchy while representing the company at a car show.

The chairman of Hyundai dropped by, throwing employees into a panic. When he decided to walk the convention floor, Confucian custom declared that his top aides follow along behind him. But it also meant that their top aides had to follow them — leading to a ridiculous trail of people that left onlookers stunned.

“I climbed to the second floor of our booth,” writes Ahrens. “There was the chairman making his way through a parting motor-show crowd, at least 20 dark-suited men following, some taking notes. The effect was that of a long, black eel snaking its way through a crowd of startled media.”