The non-surgical cosmetic procedure industry is like the “wild west”, say experts and campaigners, who are calling for the government to stop ignoring increasingly urgent pleas for the regulation of invasive procedures.

The call comes after former supermodel Linda Evangelista said that she had been “permanently deformed” after a non-surgical cosmetic procedure went wrong, raising questions about millions of women being put in danger.

In a post on Instagram, Evangelista said she had developed complications after having a procedure known as “CoolSculpting”, or cryolipolysis , which involves killing fat cells by “freezing” them with a machine. The radical change in her appearance had turned her into a recluse and resulted in a period of deep depression, she said.

Evangelista is far from the only high-profile celebrity to use cosmetic surgery and so-called non-invasive procedures – Kylie Jenner has admitted she had lipfillers and designer Marc Jacobs went as far as documenting his facelift on Instagram. On the television show Love Island – awash with perfectly sculpted young things – Faye Winter has been open about having fillers and breast implants, while former glamour model Katie Price defended a decision earlier this year to fly to a red-list country during a pandemic to have cosmetic surgery.

While the perils of non-surgical cosmetic procedures are a global issue, the issue is particularly dangerous in the UK, where anyone can carry out potentially life-threatening procedures with little to no training, said Ashton Collins, director of Save Face, a national, government-approved register of accredited non-surgical treatment practitioners. “The scale of the problem is huge,” she said.

The organisation has seen complaints increase from 378 in 2017 to 2,083 in 2020 – in one of the most serious cases the organisation dealt with, a woman said she had such severe wounds from treatment that she contracted sepsis and ended up in hospital in a coma for five days. But the number of complaints to Save Face was likely to be the “tip of the iceberg”, she said: “There are lots of severe medical side-effects that come along with these treatments – but because they’re classed as beauty treatments, anybody can do them.”

Of those treatments complained about, 86% were carried out by beauticians, hairdressers or laypeople (“who literally can teach themselves off YouTube and buy their products over the internet”, said Collins), with 81% of complainants finding their practitioner on social media. Clients were very often unaware of the risks, she said: 93% were not warned about serious complications and thought the treatments were low risk beauty treatments, 83% did not give informed consent and 84% were ignored or blocked by their practitioner when they tried to seek help.

Collins accused the government of being fully aware of the dangers of the unregulated aspects of the cosmetic surgery industry since a damning review by then NHS medical director Professor Sir Bruce Keogh in 2013. But a year-long review inquiry into non-surgical beauty treatments by the all-party parliamentary group (APPG) on beauty, aesthetics and wellbeing published in July this year found the problem had got worse because the UK government had failed to keep up with a rapid rise in demand.

Labour MP Carolyn Harris, who co-chaired the inquiry, said at the time that there was still a “complete absence” of regulation of treatments like Botox-style injections and fillers in the UK.

“It’s like the wild west,” she said. “We have people who are selling training courses which are not worth the paper they are written on. We have practitioners who are destroying the industry’s reputation by practising completely unqualified and we have victims who are scarred for life.”

At the time of the review the Department for Health and Social Care said it would look closely at its recommendations.

From October it will become illegal for under-18s to receive Botox, after the passing of the Botulinum Toxin and Cosmetic Fillers (Children) Act 2021, following a bill led by MP Laura Trott. Almost half of the complainants who came to Save Face were aged between 18 and 25; in 2019-20 it was aware of 45 treatments given to under 18s, including children as young as 15, who had had lip and cheek fillers.

“These interventions are not only completely unnecessary – no child needs cosmetic Botox – but potentially dangerous,” said Trott, who said she had seen complications including blindness, breathing difficulties, infection, filler moving around the face, rotting tissue, lip amputations and lumps.

“We do not expect something that we can easily, and very legally, get done in the comfort of our own home to be something that can blind us – but shockingly, that is the case,” she said.

Ash Mosahebi, professor of plastic surgery and council member of the British Association of Aesthetic Plastic Surgeons (Baaps), said there was a growing trend, pre-pandemic, to travel to places like Thailand or Turkey where procedures were cheaper. “Hopefully the majority work well, but if people are badly treated, and if they have come back and something has gone wrong, there’s nothing you can do. Then it is a matter of emergency treatment, and it becomes an NHS problem,” he said.

But the issue was not only one of regulation, but of equality, said Mandu Reid, leader of the Women’s Equality Party – Baaps figures show that women accounted for 92% of all cosmetic procedures in 2020.

“The crushing beauty standards and expectations that women in the public eye [face] cause serious harm, not only because of the direct consequences for women like Linda but also because of the message this sends to generations of women and girls,” she said.

The Guardian has approached Allergan, owner of CoolSculpting, for comment.