It was a well-oiled scam that targeted Beverly Hills' beautiful people.

"Dr. Daniel," armed with syringes filled with a miracle wrinkle remover, injected his patients with industrial grade silicone similar to that used to lubricate auto parts.

Daniel Tomas Fuente Serrano promised that the sensational European silicone treatment he offered would "permanently" put an end to wrinkles. Handsome and charming with his Argentine accent, he dispensed his face-saving injections at fancy Beverly Hills medical offices.

And this doctor made house calls.

Those were elegant affairs too. Women who turned out by the dozens for parties at prominent Hollywood types' homes thrown by Serrano sipped cocktails as he injected their faces with his magical silicone, authorities said. The fee was $500 per injection.

But he might as well have called himself "Dr. Jiffy Lube," according to federal prosecutors who began investigating Serrano after patients complained of nasty side effects from their treatments.

Among his clients were Diane Richie, ex-wife of singer Lionel Richie, and Shawn King, wife of CNN talk-show host Larry King.

Shawn King paid Serrano $7,000 in cash for injections administered at her Beverly Hills home in 2003. But the injections damaged her lower lip, causing a "displeasing hard bump" that made it difficult to drink liquids or talk, she complained, according to court records.

Another patient told authorities that Serrano's treatments caused three holes to form on her face that had to be repaired by a doctor.

Federal officials investigating the complaints discovered that Serrano, who also administered Botox and other substances, often filled his syringes with industrial grade silicone illegally smuggled from his native Argentina instead of expensive European silicone.

On Monday, Serrano pleaded guilty in federal court in Los Angeles to conspiracy, smuggling and use of unapproved drugs. He was sentenced to 18 months in federal prison.

At the same time, federal prosecutors named four alleged accomplices — Beverly Hills-area cosmetologists and aestheticians, which are skin-care specialists who treat the face. The four now face federal charges of aiding and abetting the scam.

Those who say Serrano victimized them have described him as a charming man with a demeanor as smooth as the faces he promised to deliver.

One former patient, a Beverly Hills woman, said in an interview Tuesday that he injected a small amount of what she thought was "the latest thing" into the area between her nose and mouth to erase her "smile lines." Two days later, she said, her eyes began swelling up and itching painfully. She broke out in allergic conjunctivitis and couldn't wear her contact lenses for more than a year, she said.

"I tried to have this guy do something small, and it was just a nightmare," said the woman, who spoke on the condition that her name not be used. "He was representing himself as a doctor and doing these injections. But it apparently shot up into my face, and I had a reaction to it. The itching went on for years, and I still have a problem."

The woman said that she asked Serrano about having an allergy test done first but that he said that was unnecessary because she had already been tested for collagen and the product he was using was similar.

She learned about Serrano through a girlfriend, who had received injections from him and raved about his work, the woman said. She got the injections at an aesthetician's office in Beverly Hills. "He was real friendly, really, really nice. He had a nice bedside manner," she said.

The woman said her face has not fully recovered, three years after her treatment by Serrano. "To this day, I have big bags under my eyes, and I'm still trying to get treated for it," she said. "It's a constant battle. I feel like I have sand in my eyes."

According to authorities, Serrano gave clients business cards declaring himself a medical doctor even though he didn't have a license in California (he was a doctor in Argentina). Prosecutors said he started out by obtaining client lists from high-end cosmetologists and aestheticians around Beverly Hills, paying them a fee if they encouraged their customers to purchase the injections.

He eventually arranged cocktail parties in which he would offer injections on the spot to guests, and he performed procedures at his clients' homes, authorities said.

As the industrial grade silicone flowed from his syringes, money poured into Serrano's pocket, prosecutors said. When investigators opened his bank safe deposit box, they found $1,160,312 in cash.

And while he presented himself as someone on the cutting edge of medicine, his associates knew him as a do-it-yourself type who filled his syringes from plastic bottles at his kitchen table, according to court documents.

One informant confided to federal authorities that she often visited "Dr. Daniel's" apartment and found him sitting at the table filling syringes.

But Serrano's San Vicente Boulevard apartment was filthy, and he did not bother to clean bottles or his tabletop with alcohol before filling syringes with his bare, ungloved hands, the informant said in court papers.

Stefanie Koch, an aesthetician at Skin Solutions, a medical spa in Brentwood where well-heeled clients can get injected with a host of substances from Botox to Restalyne to collagen, said Serrano's case shows that people often don't do enough research before having substances injected into their faces.

This "is the place of staying young and fit; even men do it now too," she said. "We work out, we stay fit, but the face — there's not so much you can do with working out the face — so you need a little help. They say, 'I can delay the knife if I do little fillers.' But there's often bruising and other things involved that they didn't calculate. They're thinking, 'It's just a lunch procedure,' but it's way more than that."

The Beverly Hills woman who received treatment from Serrano said Tuesday that "Dr. Daniel's" success in infiltrating the elite social circles speaks volumes about people's quest to erase signs of aging.

"We're all vain in Los Angeles," she said. "He grabbed ahold of a nice chunk of people in Beverly Hills. They trusted him, and he completely took advantage of them."

bob.pool@latimes.com

amanda.covarrubias @latimes.com