Having recently been plagued with a cold, I started reaching for beauty products that would make me look--and by osmosis feel--more alive, refreshed, and healthy. When I'm sick my skin is a bipolar mix, sometimes super dry and sometimes super oily. Either way, I cleanse my skin thoroughly when I'm sick (and I wash all of my makeup brushes thoroughly). These are the items I reach for which I find help bring back radiance to the face.
After a good moisturizer, I love reaching for YSL's Youth Liberator Serum foundation because it's lightweight, doesn't feel heavy on the skin, but gives a fair amount of coverage and ultimately makes the skin look radiant and ever so slightly dewy. I apply with a flat topped kabuki brush.
Sick day skin is all about the face so I am sure to use my heavy duty under eye concealer (a well-loved pot of Bobbi Brown Corrector in Light Bisque). Then I apply a highlighting concealer pen over that as well as the high points of my face. After that, the rest of the face is kept simple with a soft blush, and neutral glossy lip (this one is Blush Essence). I also recommend redness removing eye drops (I personally love Rohto drops but for those who find them too strong, the Clear Eyes cooling ones are similar but less stinging).