Is the tissue hanging outside pink at all or pretty much dark/cyanotic? Keeping the prolapse tissue moist with oil or honey at all times until it stays inside is important. If it dries out it will die. If it is already staying dark, it may be necrotic, but since she is a silkie, it may be hard to tell. It can take days for some prolapses to stay in, so I would keep trying to push it inside. Some chickens do not survive a prolapse, but many do. It can happen again. I wish you luck treating her. Make sure that she is getting feed with 4% calcium, and give calcium until the prolapse stays in. Can you feel an egg inside?