Meghan Trainor apparently had one fewer as an ideal experience with Botox. She recently revealed that she has found it difficult to smile since undergoing lip flip surgery, an increasingly popular non-surgical treatment aimed at making the upper lip appear fuller.

On a recent episode of her podcast “Workin’ On It,” the singer said that she “got too much Botox” and “couldn’t smile anymore.”

“This is as big as I can smile,” she said in the video, looking directly into the camera in demonstration. She later added that her “face hurts when you smile – if you even try.”

Trainor, who explained elsewhere in the episode that she had a positive experience with Botox treatment before her lip flip debacle, is among a seemingly growing number of people taking up the trendy lip flip in recent years -have turned to cosmetic procedures.

Dr. Rosanne Paul, an assistant professor in the department of dermatology at Case Western Reserve University School of Medicine, told HuffPost that she believes the lip flip procedure has increased in popularity over the past year or two.

What exactly is a lip flip procedure? And is Trainor’s experience common? Read below to see what experts say about the popular trend (and some key things to keep in mind if you’re thinking about getting Botox overall).

The procedure is for those who want more “volume” in their upper lip but may not want to have a product injected into their lips, such as a lip filler, Paul explained.

“That’s where Lip Flip was developed,” she said.

If you get a lip flip, a doctor will inject Botox or another botulinum toxin into the orbicularis oris muscle in your upper lip to prevent contraction.

“This is the muscle that activates when you purse your lips or kiss,” said Allison Rojas, a registered nurse in the Hansjörg Wyss Department of Plastic Surgery at NYU Langone Health. “The idea is that by relaxing this muscle, the lips will bulge outward and appear fuller without the use of fillers.”

“This procedure is an alternative to fillers, especially for people who want a fuller-appearing lip without actually increasing the volume of the lip itself,” added Dr. Eva R. Parker, assistant professor of dermatology at Vanderbilt University Medical Center, added.

This has not been shown to be a common side effect, and a lip flip and Botox overall are considered generally safe. However, lip surgery can have temporary side effects on your smile for several reasons.

Dr. Sam Most, a professor of otolaryngology at Stanford Medicine, told HuffPost that while he doesn’t believe there have been studies yet on the side effects of the lip flip procedure and the ability to smile normally, he but believes this is more common than side effects from Botox in areas such as the eyelid – which he says occurs “in about 1% of cases”.

“I think it’s more common because it’s a more technically demanding injection,” he said of the lip slap. “So I think the risks are higher.”

Most explained that although a provider “injects very small amounts of Botox” when performing a lip flip, it is possible for the Botox to spread easily, just as with injections made anywhere else on the body.

“If it spreads a little bit or if it’s not injected in exactly the right place, it paralyzes the muscle that you didn’t want to paralyze,” he said, later adding: “Around the mouth, the problem is that you have that “It can spread or inadvertently inject muscles you don’t want to reach, which can affect your smile.”

Your smile could also be affected if you are injected with too much Botox during the procedure.

“If you put too much in, I think it will be difficult to lift the corners of your mouth and therefore difficult to smile,” Most said.

Dr. Shaun Desai, associate professor of facial plastic and reconstructive surgery at the Johns Hopkins Department of Otolaryngology-Head and Neck Surgery, told HuffPost that it is “not typical to lose the ability to smile normally, if a lip flip procedure is performed conservatively and conservatively on the right patient.”

But he said: “If the Botox is injected into the wrong part of the facial muscles or too much Botox is injected, it could potentially distort the smile.”

However, the good news is that, like other Botox procedures, the effects of a lip flip are only temporary.

“Botox is temporary. Lip injections generally last eight weeks,” Parker said. “This means that complications such as asymmetry or excessive relaxation are not permanent and will go away when the Botox wears off.”

The Cleveland Clinic states that the lip flip typically lasts between two and five months. So if you’re not happy with the results of the cosmetic procedure – as was the case with Trainor – rest assured that the effects of Botox will eventually wear off.

First of all, Paul said that people who have had a bad side effect from Botox before should consider not getting it again in the future. Additionally, she wouldn’t recommend Botox to people with certain muscle and autoimmune diseases, such as Lambert-Eaton syndrome, in which the immune system attacks the areas where your nerves and muscles connect, or myasthenia gravis, which is a weakness the skeletal muscles.

Possible side effects of Botox treatment in general include pain, swelling or bruising at the injection site, headache, neck pain, flu-like symptoms, stomach upset, eye irritation and temporary drooping eyelids (ptosis), the Cleveland Clinic states that Botox is not for pregnant women or is recommended for people who are breastfeeding.

Paul added that “Spock Brow,” or an exaggerated raised eyebrow, is another possible side effect of Botox.

“Some people naturally have facial asymmetry, so the main risk is that the eyebrows become abnormally raised,” she said, adding that people can also experience heavy eyelid as a possible side effect.

“The biggest risk is being dissatisfied with the cosmetic appearance after the injection,” Desai added.

So if you’re considering a lip flip procedure or Botox treatment, Parker emphasized that it’s “essential to have cosmetic procedures performed by experienced and trained injectors who are qualified and licensed to perform such treatments.”

As always, discuss any concerns or questions with your doctor.