I have psoriasis, and now have white spots? how do i cover them quickly? airbrush tanning? self tanners?

I am in a wedding in 2 weeks, and have to wear a strapless dress, and it is very badly blotchy and spotty where the scales first were, they haev dried out and jsut left white spots which look slike sun spots and i want to know overall what is the best way to get pigment back in my skin? tanning i woudl ume for an overall fix, but im not even sure on that.. but for a quick fix that looks natural shoudl i try a self tanner? will that even work on the spots? or shoudl i try mystic/airbrush tanning... will taht work better or at all? i jsut want to look as natural as possible, so id liek to avoid using makeup, and having it rub off on my dress or something... any help or suggestions woudl be greatly apprectaied!!!!! thank you!!!!!!! i was jsut diagnosed and am new to dealing with evrything! my slef esteem has already gotten way bad, and i just feel uncomfortbale in my skin.... i have guttate psoriasis, if that makes a differnece, so it is pretty much only spotty on my arms and legs..