London - Like many of her friends, Lydia Smith, 28, longed for fuller lips. "I wanted them to look like the pout I make when I pose for a selfie," explains the hairdresser from Castle Bromwich. "More clients were coming into the salon having had their lips done, so I thought I’d try it, too."
Lydia first had lip filler two years ago, given to her by a woman she met through work. Lydia didn’t ask what qualifications she had, and no medical history was taken.
The procedure took place in a "beauty room" at the back of a hairdressing salon, where a product was injected into Lydia’s lips.
"Although one side was bigger than the other and I had to pay her to re-do them a few weeks later, I didn’t have any major problems," she says.
"But when I went back to the same lady a year later, she was using a cheaper product and said the procedure would cost £170 instead of £220."
While the first procedure had been uncomfortable, this time Lydia was in excruciating pain.
"Every time the needle went in, it felt as though she was injecting acid - it was horrific," she says.
"To combat the pain, she injected local anaesthetic into my gums, but she kept hitting a nerve and my chin filled up with hard bumps. The more pain I was in, the more she seemed nervous and panicky."
Within minutes, Lydia’s lips had swollen to three times their normal size, with pronounced lumps and severe bruising. She also felt sick and disorientated.
"My mum, who picked me up afterwards, was horrified," recalls Lydia, who was advised to massage her lips to break up the lumps and help the swelling subside.
"But they were too painful to touch. For seven months afterwards, I woke up every morning looking as though I’d been punched in the face."
When she complained, the practitioner suggested ice packs and antihistamines to reduce swelling.
Once the preserve of celebrities, cosmetic "tweakments", including dermal fillers to plump up areas of the face, are becoming as mainstream as a manicure to a generation of young women reared on before and after pictures of the Kardashians and used to digitally re-shaping their own faces in photos to post on social media.
But few realise the risks they run - not just to their appearance but also to their health, when things go wrong.
In unskilled hands, fillers, which are used to plump up lips or cheeks, can lead to permanent lumps and bumps, raw, sensitive lips, infection and abscesses. Worse, they can lead to tissue death, vascular occlusion - when filler is injected directly into an artery, causing blindness - and life-threatening complications.
Dr Anne Mendelovici, a London-based aesthetic doctor, explains that some girls ask for their lips to be plumped to two or three times the size of their natural lips, "which no responsible surgeon would agree to".
"We’re almost looking at a new beauty ideal - and it’s as far from the natural aesthetic as it could possibly be. Not only is it a disaster aesthetically, [but] the gross over-stretching of delicate skin can result in permanent and disfiguring scar tissue."
Dr Max Malik, a Harley Street cosmetic doctor, eventually removed Lydia’s lip filler by dissolving it with injections of hyaluronidase, a naturally occurring enzyme.
"You can never, ever be gung-ho with someone’s face," he says. "Administering filler is a medical procedure which involves a product being delivered to all levels, even down to the bone.
"The potential for damage, including infection and skin necrosis - where the tissue dies - is huge. I know of cases where, in unskilled hands, the blockage of a blood vessel has led to blindness and stroke."
Dermatologists and plastic surgeons are concerned by the alarming rise in girls as young as 14 being lured by adverts on social media sights such as Snapchat and Instagram, where unskilled practitioners working in non- medical settings, such as beauty salons, advertise cheap ‘Love Island’ packages.
Dr Nick Lowe, a dermatologist and cosmetic doctor at the Cranley Clinic in London, warns that self-proclaimed social media "medical influencers" are not just putting young people at risk physically but also harming their mental health.
"Girls are having treatment at a time when they don’t need it, and we’re seeing body dysmorphic syndromes as a result [where a person worries obsessively about their appearance].
"It’s extremely troubling. The standards set by Instagram and Snapchat filters are impossible to meet in real life," he says. "To stop the widespread uncontrolled use of fillers and Botox, they simply need to be classified as medical procedures.
"Unfortunately, though, nothing is being done about it."