The 'Keeping Up With the Kardashians' star - who has eight-month-old daughter Stormi with boyfriend Travis Scott - recently revealed she'd had her pout plumped again, less than three months after deciding to opt for her natural shape, and now her nurse has explained the 21-year-old beauty just likes a bit of help to "add a little pout".
The injectables expert, who works at Motykie Med Spa, told Refinery29: "Just a small touch-up on her lip fillers. She doesn't do anything else, just lip fillers.
"My philosophy has always been 'less is more.' We're more of a conservative, natural practice, but the size does depend on the patient. Some people like to go really big and some people like to keep it natural.
"We went the natural route for [Jenner's] touch-up since she's so naturally beautiful and a new mom. A lot of people get fillers because they're getting older and losing the hyaluronic acid in their lips, but she's so young that it has nothing to do with aging.
"For her, it's just about adding a little pout to her lips."
The 'Life of Kylie' star has previously told how she opted for lip fillers when she was just 17 after being teased over her small mouth, and the nurse admitted the treatment is a great safe procedure to "boost confidence".
She said: "We see people of all different ages come through the Motykie Med Spa for different procedures, but I definitely have younger people, especially women between 21 and 30, come in for the lip fillers.
"If someone has had small lips all their life, was teased in high school, and are looking for a safe cosmetic procedure to boost their confidence, this is it."
The Lip Kit mogul first admitted in May 2015 she had been using fillers and explained last year she took the plunge after a guy thought she'd be a bad kisser because of the naturally thin shape of her lips.
She said: "I was 15 and I was insecure about my lips. I have really small lips. And it was like one of my first kisses and a guy was like, 'I didn't think you would be a good kisser because you have such small lips.' But I took that really hard.
"Just when a guy you like says that, I don't know, it just really affected me. I just didn't feel desirable or pretty. I really wanted bigger lips."