I've had luck with liquid hand soap (SoftSoap brand) and cold water. Dampen fabric, apply soap directly to the stained area and gently rub it in, run the stained area under cold running water. Repeat if necessary.

Treating with Clorox 2 detergent may also help if the soap doesn't do the trick.

It might help to spot-treat the area with a drop of any good liquid laundry detergent that has enzymes in it. Massage gently with your finger, let set for up to 15 minutes, then wash in the proper detergent for silk. The enzymes should eat up the blood (a protein).

One's own saliva will remove blood from fabric, better than anything else. (Another person's saliva won't work as well, because each body chemistry is different, or so I have been told) This is the first thing to try, before anything else. It is a solution that quilters use when a needle has pricked our finger and blood has gotten on a quilt. It works. Ask me how I know . . .

You could try some hydrogen peroxide too - I've seen that help fade blood stains. Enzyme pre-treaters that work aggressively on protein could be problematic for silk since it is protein-based. I would go back to an old standby - *plain* blue Dawn dish detergent. Not the bleach / Oxi / moisturizing kind, but the original kind they use to clean wildlife with after oil spills. It can take a long time to work (overnight), but seems to always get things out.

Too late to tell you right now but if the stain is small, the best thing to do as soon as it happens is spit! Saliva is full of very strong enzymes that startbreaking down proteins (blood) as soon as it hits them. And it will not hurt the fiber if you rinse it out as soon as the blood fades.

It sounds crazy but I have had experience with this on fabrics that could not be washed in the usual ways (dance costumes, etc). Make sure your mouth is clean and think of lemons, work up some saliva and spit it on the stain, then sit and watch it fade away!

I would use hydrogen peroxide. Spit can work, but since you treated it with an acid already, it might be more difficult to remove now. Since your blouse is not white, I would use 50/50 water and peroxide, and dab it on the stain. It should slowly disappear. Then wash it, or dry clean it, according to the care label. If worst comes to worst, wet the entire blouse, and lay it stain side up in the grass, in the brightest sun you can. The sun will bleach the stain out and will not harm the blouse.

I would NOT use any cleaner or detergent with enzymes on silk. Detergent enzymes eat protein (stains). Silk is a protein. So, enzymes will actually make silk or cashmere weaker over time.