Sunburns to your legs are known to be followed by the development of spider veins
. Standing and sedentary occupations are definitely aggravating factors.
You can try to avoid long periods of standing or sitting. Elevate your legs to give your veins a "rest". Adjust your chair at work not to be too high, if you cannot, then put a few books under your feet. This will lessen the pressure on your thighs and thus the pressure on your veins. Try to keep your legs cool. You may consider wearing support stockings.
I do hope that you have found something helpful and Informative.