The redness, puffiness and abundant mucus that you suffer when you have a cold or the flu should automatically grant you a free pass to stay under the covers until you feel rosy again.
Unfortunately, work, family, and other responsibilities may mean that you must get up and face the world -- no matter what that face looks like.
"Just feeling bad can make you feel not so attractive," said Dr. Ronald Turner, a cold and flu expert and professor of pediatrics at the University of Virginia.
And a Rudolph-red nose on top of the fatigue, aches and stress of being sick hardly helps the way a person looks.
Fortunately, experts say that after lots of rest and fluids, there are a few simple things you can do to look more refreshed.
"When you do have the rough night, you wake up in the morning and you look like hell," said Matin Maulawizada, a New York-based makeup artist whose work has been published in various magazines, including Vogue, Vanity Fair and Cosmopolitan. "At least they can make themselves look better and feel energetic."
A healthy looking face needs a healthy canvas. Unfortunately, the skin can be hit hardest during an illness, looking dry and scaly and even pocked with cold sores.
A cold or flu, medications and dry air are just a few of the things that can strip skin of moisture. And dull, dry skin can emphasize the fatigue that comes with a cold or flu.
In addition to dry skin, the most obvious sign that you are not feeling -- or looking -- your best are the red areas around the nose and eyes, exacerbated by rubbing with fingers or tissues.
"These are prime areas for cold sores and chapped skin when you are sick," said Carmindy, a New York-based makeup artist and resident makeup guru on TLC's show "What Not to Wear." "Also eyes can get red and runny."
A rich moisturizer can help restore some of that water to the skin and soothe redness and itching, creating a more vital, energized look, she said.
Soothing irritated areas also helps to create a smooth canvas for a concealer that can hide the redness.
Maulawizada said that a slightly dry concealer with a lot of coverage, a cream formula for example, will last longer after it is patted over the red areas around the eyes and nose.
"You want the skin surface to look pretty," Maulawizada said. "When you look at the mirror, you'll feel 100 percent better."
But there is one area on the face where a bit of color makes a big difference when you are sick -- in a good way.
"If you don't want makeup makeup, you can do blush," Maulawizada said.
A healthy flush of pink in a shade that appears naturally in your skin can help you look fresh and awake.
"Take your index finger, press it, and see how red it is," Maulawizada said. "That's like a good gauge of color. These are the reds that are in your skin."
Lighter-skinned women look best in sheer fuchsias or bright pinks, Maulawizada suggested, while women with darker skin tones should choose a raspberry color.
But no matter how rosy the face, puffy, baggy eyes can signal illness from a mile away.
"The skin [around the eyes] is thinner, and the tissue underneath is more loosely attached," Turner said. "There is more room for fluids to accumulate."
Constricting the blood vessels under the skin can help to counteract the fluids sloshing around in the face due to congestion.