tanning tips?

I avoid tanning because the one time I did it looked horrible as I have all these pores/open hair follicles on my legs. I don't understand how people get such perfect smooth looking tans
And suggestions? Product recommendations? Something that's easy. I don't care if it doesn't last, I just want it for my date on Friday night, I'm so pale and need a tan asap. I don't have time to go to a solarium and not sure if I should get a professional spray tan as you can't shower or sweat for 24 hours. 
Also, would it ruin my white dress if I sweat?