LAST month, Charice Pempengco, the petite Filipino teenager whose knockout voice has wowed Oprah and millions worldwide, caused a stir of another kind.

To prepare for her appearance on the Fox show “Glee” this fall, Ms. Pempengco, who is 18, got Botox injections and a skin-tightening treatment called Thermage. “I want to look fresh when I appear before the camera,” she said on Philippine television during the visit at which her doctor, Vicki Belo, injected her jaw.

Outrage ensued. Doctors, child-rearing experts and others  including New York magazine and Psychology Today  chimed in to lament the regrettable message sent to young fans of “Glee,” a show with a theme of self-acceptance. Even the celebrity blogger Perez Hilton was apoplectic, pronouncing what Ms. Pempengco had done, “SICK!!!”

But like it or not, Ms. Pempengco has plenty of company. According to the American Society of Plastic Surgeons, last year, botulinum toxin, which is sold here under the brand names Botox and Dysport, was injected into Americans ages 13 to 19 nearly 12,000 times, including some teenagers who got multiple doses. The number represented a 2 percent increase from 2008, the society said.