'RHOC' Star Elizabeth Lyn Vargas All Smiles After Ex's Armed Standoff

What a difference a day makes -- Elizabeth Lyn Vargas is looking totally cheerful 24 hours after a terrifying experience where she feared she might be killed by an ex.

Check out these pics of the 'RHOC' star Wednesday outside her Newport Beach home ... where just yesterday her ex-boyfriend was armed and threatening her life. As you can see, she's all smiles now as she hangs out with a friend and her dog.

Looks like ELV was chatting up a guy -- possibly a neighbor -- just before or after walking her husky pooch. Whatever they were discussing, he got her to LOL ... no small feat considering the ordeal she just survived.

Like we told you, Liz had to get the cops involved after claiming the guy, who she'd briefly dated, started acting erratically -- constantly following her around, and allegedly asking for money. Things came to a head Tuesday, and she felt compelled to report it to cops as attempted extortion.

The situation escalated when the guy showed up armed at her home -- allegedly roughing her up before letting her go ... but barricading himself in the home in a standoff with police.

Cops say 33-year-old Ryan Geraghty was charged with assault with a deadly weapon, burglary, felon in possession of a firearm and extortion for the incident.