Kreviazuk invited Lavigne to continue working in a Malibu, California house she shared with Maida, which contained a recording studio.
Lavigne released four official singles from the album, and two promotional singles.
"Fall to Pieces" was released as an airplay single in North America and Australia.
Kreviazuk suggested Maida produce songs for the album, an ability Lavigne did not know.
Maida produced five songs, including "Fall to Pieces", which he co-wrote with Lavigne.
Carly Carioli of Blender magazine also agreed, stating "she has deepened and darkened her sound without sacrificing her platinum-plated melodies".
Kelefa Sanneh of Rolling Stone praised Lavigne's vocals, "blankness is what makes her best songs so irresistible.I'm really picky with my sound." Regarding the album's theme, Lavigne stated, "I've gone through so much, so that's what I talk about.... Lavigne broadened her repertoire with the help of alternative rock music with a goth rock edge along with the traditional pop-punk tunes.Under My Skin fits into a variety of musical styles because of Lavigne's mix of pop and rock genre influences, similar to Lavigne's first album, Let Go.The Guardian's Alexis Petridis lambasted the album, calling it a "flesh-eating virus" and criticized the lyrics, stating "the music is so anodyne that you don't pay much attention to Lavigne's lyrics. Under My Skin is included in an article about Petridis' worst reviewed albums of modern times.Under My Skin was released on in the United States and worldwide.Under My Skin has been described as alternative rock.