Britney -- Nervous Train Wreck
Brit-Brit looked a bit nervous as she left a Beverly Hills tanning salon yesterday ... snacking on what's left of her fingernails. 
Wearing a swanky green weave holder, she chomped on her nails while waiting at a stoplight ... perhaps musing about how she'll be the only starlet left in Tinseltown come summertime -- or praying the paps wouldn't get a shot of her goods as her tank top strap fell down her arm.
At least she's nice and spraytanned for her close-ups, y'all!
