Do: Avoid water for the first 24 hours. That means no showering. You can take a cool bath, however. Just keep in mind: lash extensions are water-resistant, not waterproof.
Don't: Get your lashes directly in heat's way. "So if you're baking and you open up the oven, let the heat come out first," says Liv Contreras, co-owner of Lashfully, a San Francisco-based eyelash-extension lounge. Lash extensions are heat-resistant, not heatproof.
Do: Use a heated lash curler if you'd like, but only if it's on a very low heat.
Don't: Use heavy eye creams or oils near the extensions since they can loosen the glue.
Do: Use mascara if you'd like, making sure it's not waterproof, and that it's only applied at the tips. Just be sure to use an oil-free product when removing the mascara.
Don't: Use cotton on the lashes, as the fiber will attract lint. Instead, use a soft cloth and water when removing liner and shadow.
Do: Feel free to swim. "You just want to spray them afterwards with bottled, nonchlorinated water because that will prevent the adhesive from breaking down," explains Liv.
Source: Flickr User Shandi-lee