Byline: Elysa Gardner

NEW YORK -- A female singer in her teens emerges seemingly overnight with a multiplatinum smash, winning millions of fans and launching scores of imitators. A couple of years pass and, poised on the brink of adulthood, she must release a new album that proves her initial success was no fluke and shows signs of personal and creative growth.

A few years back, the young woman in that position was Britney Spears. But a different kind of artist will face the pressure Tuesday, when Avril Lavigne's second CD, Under My Skin, arrives.

Not long after Lavigne's debut, Let Go, was released in 2002, the then-17-year-old Ontario native found herself tagged as a sort of anti-Britney. The ruggedly accessible, tomboyish presence that Lavigne projected in hit songs such as Complicated and Sk8er Boi and their videos was more appealing to many teenage girls -- and more comforting to their parents -- than Spears' increasingly elaborate attempts to shock and seduce like her idol, Madonna.

And while Lavigne crafted many of the tunes on Let Go with a team of veteran songwriters/producers known as The Matrix, many critics thought her capable of more autonomy.

Two years can be an eon in the fickle world of pop music, though, and Lavigne now faces competition from other teen crooners obviously inspired by her hook-laden, guitar-driven sound, among them Lindsay Lohan and Hilary Duff.

"Avril has to watch her back now, the way that Britney did, because you have new girls who will try to take what she helped shape and make it that much more commercial," says Craig Marks, editor of the music magazine Blender.

The less-than-ecstatic reception that has greeted Don't Tell Me, the first single from Skin, underlines the challenge that Lavigne faces. Airplay Monitor editor Scott McKenzie says the track is "hovering" at top 40 radio. "It's hard to tell if stations are embracing it because they want to or because she's a well-promoted artist they've had success with before."

Lavigne does not pretend to be blase about her acceptance on the airwaves. "Radio means...