Popular DIY beauty trends on TikTok could be dangerous and harmful, health groups have warned.
Examples include applying bleach to whiten teeth, removing moles at home and using eyelash glue to make lips appear larger, BBC News found.
When these videos went viral, they encouraged others to copy so-called "beauty hacks," which could cause permanent damage, the groups warned.
TikTok told BBC News that the videos do not violate community guidelines.
However, the British Association of Dermatologists, the British Dental Association and the British Skin Foundation - who have seen the videos - have issued warnings today about copying these treatments on social media.
"It is important to remind people that social media should not be used as a primary source for dermatology problems," said the British Association of Dermatologists.
"When it comes to skin, it can lead to unnecessary fears or panic where it's not needed, wasted resources like money for products that can't treat medical problems, potential delay in treatment, and potential worsening of one's psychological health.
A government spokesperson for the Department of Health and Welfare said he was "concerned about reports of dangerous and misleading cosmetic beauty" hacks "circulating on social media."
"Scrape"
Some videos the BBC has seen promoted using chemical or physical methods to remove moles. Experts recommend having all moles checked by a professional before removal.
"There is no 'safe' way to remove a mole at home," said Dr. Ross Perry, NHS GP and medical director of Cosmedics Skin Clinics.
"This must be done by a qualified doctor or dermatologist who is trained and knows what they are doing.
"Using chemicals or trying to 'scrape' off a mole could lead to infection, bleeding, scarring and deformity of the area."
A particular method recommends applying eyelash glue to the skin.
Dr Adil Sheraz, a consultant dermatologist with the British Skin Foundation, said doing it to create a plumping effect could lead to permanent scarring or disfigurement.
"The eyelash glue contains cyanoacrylate which is known to be a contact allergen," he said.
"Applying a potentially allergenic chemical to the lips could cause a serious reaction."
Meanwhile, some cosmetic surgeons told BBC News they've also seen social media videos of Botox at home or lip filler kits.
Apply the bleach
TikTok videos with the hashtag "teeth whitening" have amassed approximately 284 million views. Some recommend bleaching your teeth to avoid "expensive" over-the-counter treatments.
According to UK law, teeth whitening products can only be sold directly to the public if they contain no more than 0.1% hydrogen peroxide.
And anything above this level should be provided or used under the supervision of a dentist.
Household bleaches may also contain other bleaching compounds.
The British Dental Association said administering the wrong products at home could cause "permanent damage".
"The BDA is concerned about the do-it-yourself trend of whitening teeth with levels of hydrogen peroxide that are higher than those allowed in over-the-counter products," a rep said.
"Using higher concentrations without supervision, as some videos claim, increases the risk of damage to teeth and gums, including burns to the mouth, tooth and gum sensitivity, as well as sore or inflamed gums."
"Skin cancers"
A viral video copied to TikTok suggests a way to apply sunscreen to create a contour effect.
"Skin cancers affect all areas of the face," said Dr. Vishal Madan, of Stratum Dermatology Clinics.
"Using sunscreen on some areas and missing others to create a pattern may be trendy, but UV damage to the tanned area will invariably increase the risk of skin cancers in that area.
"Not only that, repeated exposure to UV rays in these areas will cause them to age prematurely, so over time the skin will appear mottled and uneven."
Some cosmetic mask treatments promoted in TikTok videos could also be harmful, said Adonia Medical Clinic Founder and Medical Director Dr. Ifeoma Ejikeme.
"It's dangerous to put citrus on your skin and then go into the sun," he said.
"It can cause inflammation of the skin expressed as burning, redness and blistering."
The BBC shared these videos with medical experts and TikTok, but the company said these videos don't break their rules.
"Keeping people safe on TikTok is a top priority," added a rep.
"Our community guidelines make it clear that we will remove content that promotes dangerous behavior or activities that could cause serious injury or physical harm.
"We are continually evaluating our policies and processes to make sure we do everything possible to keep our users safe."
