How do you protect your skin when you have to sit by computer for a long time?

I don't think the computer has anything to do with your skin condition. There are no 'harmful rays' from monitors these days (and never were except, perhaps, in the long distant past of green screens). I think I would look at your general environment and activity. Do you, for example, get enough fresh air and exercise? Is your office dark and dingy or light and airy? Do you have heating or air conditioning that makes the air dry? It is even worth checking your posture. Do you sit with your back straight and the keyboard level with your elbows; are your feet resting comfortably on the floor? The most common ailment for computer users are tired eyes, backache and wrist injuries. The last two are always due to incorrect posture often exacerbated by using the wrong kind of chair. When using a monitor, you should look away from it every 10 minutes or so and focus on something in the distance - look across the room or out of the window for a few seconds. This exercises your eye muscles and helps to keep them in trim. Even if your eyes don't actually get painful, without a change of scene, they will become tired and watery.

Sometimes taking a few minutes to stand by the window with sunlight can help improve the color and tone of your skin. Sunlight is essential for beauty. And, while you should always use high SPF and skin care products, sunlight does help. It can help and hurt. Just try to get some more sunlight. That works for my skin and I'm very pale. If I spend too much time indoors at the computer, I get the same problem. But, fifteen minutes outdoors makes me look and feel human again. Thanks for sharing your beauty concerns. I use mineral girlz makeup and tht also helps the tone and condition of my skin. I posted their banner on my profile if you're interested.