SUNBURN.... help me ASAP!!??!!!?

right... i've gone and been extremely foolish and i completely forgot to put suncream on when i left the house this morning - and then i never went back to get some because i didn't expect it to be overly warm, but it turned out to be scorching! and now i'm extremely burnt - and my face is BRIGHT red, as is my chest and my arms ... this wouldn't normally be a huge issue, i'd just take it a consequence of stupidity - BUT, my prom is on friday - and my dress is completely strapless... i need to get rid of the redness (with minimal peeling if possible!) before then. I am having a spray tan on thursday, so i'm really hoping that may disguise some of it, but does anyone have any idea about how i can get the redness down?? please, please, please help!!