M.S.
Lol! I am a dance teacher and have heard of a ton of costume disasters from parents...everything from loosing it ("I think the cleaning lady threw it away"!!!) to the dog actually eating holes in it (which just happened this year)!!!
NEVER wash it in the washer or dryer (which I'm sure you know now). The best way to get the wrinkles out is to hang the costume upside down (which will keep the skirt fluffy as well) and hang it in the bathroom (away from any water) for a few days. The steam from the shower will usually release any wrinkles in the fabric.
The better news is since pictures are done you probably only have the recital left....and costumes are very forgiving on stage...you won't see a thing! : ) Hope that helps!!!