How Can I Stretch Out Silk??

You might try Downy Wrinkle Release.....it relaxes the fibers to allow the wrinkles to be brushed/fall out, so maybe it will relax those in your blouse as well. I don't like my clothes to fit tight so I use it on all types of fabrics, especially the tops, to enlarge them a bit before I put them on so I'll feel more comfortable wearing them. I think I would take the dry blouse and spray it till it is soaked then try gently stretching it at angles to the weave, and hang it up till it dries. Ironing with a steam iron usually helps to stretch it some as well.

I tried to do a google search on stretching silk but most of what came up was how to stretch individual threads (like for needlework or beading) and stretching it over a frame to make a canvas out of it. Nothing about actually restretching a garment that shrunk.

I'm not sure you'll be able to stretch it back out. But try google to see if there's anything there that might be helpful.

Press it carefully and give it to a friend who is smaller than you are.

I don't know if I have ever shrank silk before but you can try wetting it in cold water and then stretching it while it is still wet. That sometimes works with other fibers. Worth a shot I suppose.