Borderline Brit; STAR'S MEXICO DASH TORMENT.

HER once beautiful face now wears a tragic, haunted look and her black-ringed eyes stare out in despair.

Her fingernails chewed down, she nervously clutches her dog - before setting off just hours later on one of her infamous nights on the town.

This is Britney Spears looking every inch a woman on the brink of a breakdown in the latest bizarre episode of her life.

The fallen star, 26, staged an extraordinary dash to Mexico amid fears her parents want her sectioned. One worried pal said: "She's a woman teetering on the brink of a precipice."

Tormented Britney set up elaborate decoys involving two private jets, dozens of security guards, limos and police to fool pursuers.

She and lover Adnan Ghalib, 35, checked into a hotel in Baja, Mexico, at 2pm local time on Wednesday.

But aides hoaxed the press into thinking she was off to New Jersey or Hawaii - and put minders there. In New Jersey, guards even called police for help as photographers swarmed.

By 8pm on Thursday she and Adnan were back in Marina Del Rey, Los Angeles, with Britney looking drained.

Yet hours later they hit the town. She had a pink wig and a jacket with the slogan "F**k Off Lover Boy". At one stage she sucked on an inhaler.

Her pal added: "She's vulnerable and he's got her all over the place. It appears he's taking advantage."

Last week, Britney went to hospital in restraints after a custody row.

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CAPTION(S):

2PM WEDS BAJA, MEXICO Britney and Adnan are spotted driving in Mexico and, inset, the hotel where couple stayed; 8PM THURS MARINA DEL REY, L.A. Cud dling pet dog at gas station stop to buy drinks and cigarettes; 3AM FRI LOS ANGELES The troubled singer catches her breath after her hectic round trip and takes a gulp from her inhaler; BACK OFF: Message on jacket Pictures: XPOSURE/X17