1. If the veins on your wrist show through blue-purple, that means cool tones. If the veins are more green, that’s warm. And if they’re neither, or in between, that’s neutral.Knowing your skin tone can help you pick your perfect lipstick! For example, warm undertones play well with orangey reds, while cool pairs are best with blue-based reds. The more you know! 2. Every three months. It's dark and wet inside that tube, and bacteria LOVE it. If you don't use up mascara quickly, try a mini mascara like this one. 3. It depends. If the lashes fall off naturally because the glue dissolves, maybe not. If they get yanked or tugged off accidentally, maybe. 4. YES. Biting nails can create damage in the nail bed that allows bacteria to breed, and basically you are 30 seconds away from a disfiguring nail infection. Curb the impulse to chew with a pretty manicure. Use a polish that strengthens to help heal the damage, like this one. 5. Parabens are preservatives, and while there's no science that proves they are harmful, research is ongoing, so some people choose to avoid them as a precaution. 6. Science says no, boo boo. A virgin hair tapers to a fine point, and a shaved hair may have a blunt end, so it’s possible that the regrown hair appears darker. But no. Shaving does not change anything about how your hair grows. 7. It's shorthand for a beauty balm. It's got SPF, moisturizing, foundation, and primer in one tube. Many women use it as a first step in their makeup routines as a base for all other elements. 8. Not entirely true or false. Your BFF may swear by it, but according to the UKHealthCentre, that’s because it varies from person to person. Those with thinner hair might experience a growth return that is more sparse. 9. It clogs and stretches your pores, as well as makes your skin age faster, in general. 10. It depends! Dermatologists say about twice a week as a baseline. Oily skin might require more frequent exfoliation, and older skin might be too delicate for anything over once a week. 11. Not really... HOWEVER, you have to be clean about it. According to a study by the Contact Lens Association of Ophthalmologists, eyeliner applied to the inner line pretty much heads straight to your tear duct, which can easily cause infection. So sanitize frequently. Think sharpening both before and after use.For the best results, use a really creamy pencil that won't tug or pull skin. Try this one. 12. You in THAT much of a hurry? Unfortunately, cancer experts do not recommended this. You need those sweet SPFs, and combining two products that are not formulated together can break down the SPFs and make the sunscreen less protective. Additionally, the sunscreen needs to be applied first to be fully absorbed and effective. So, according to medical professionals, if you have a concealer with SPF and that’s the only SPF you use, make sure it goes on first with no additional moisturizers underneath it. 13. Yep, 100%. While there's no hard and fast rule for when perfumes expire, any changes in color or smell could indicated that it's past its prime. Head to Macy's during Beauty Scene for samples, extras, bonuses, and perks on all your makeup purchases! Courtesy of Macy's All images from Thinkstock.