What is Vanessa Hudgens trying to hide?

The former High School Musical star kept her mouth covered up with her iPhone as she left a yoga class in Ventura, Calif., on Wednesday.

But it didn't stop there. The actress also shielded her lips a little later in the afternoon as she grabbed lunch with a pal -- although this time she used her hand to hide any damage, not electronics.

Hmm ... that's a little suspicious, V!