You can also try a soak in cool water and a ColorCatcher sheet. They should be at the supermarket with the laundry stuff, but Amazon has them too. It'll pick up any surplus dye -- red is notorious for running. A sink or a basin of cool water, put the ColorCatcher in and smushel it around a bit, then lay the scarf in the water, pressing it gently down to get the water soaked through. Don't agitate or scrub, but just a little motion. Let it sit for ten minutes or so, then drain the sink and let the excess water run out. Roll up the scarf in a clean towel that you don't mind getting red/pink on. Press on the rolled up towel to soak out the water, then let the scarf dry flat.
ETA: just the way Catrin told you, only without the vinegar. Sorry, Catrin, I somehow managed to miss your post.