As long as the scarf dries completely -- and I mean it has to be bone dry, not the tiniest bit damp -- before you remove the wires/pins, then it should definitely hold its shape. I think your pattern called for steam-blocking because itís a lace scarf and because wool tends to become weaker when wet. You were probably advised to submerge, however, because you wanted to add length to your scarf, in which case wet-blocking is your best method. Just remember to be gentle, like Abby mentioned. Actually, from your description it's obvious you were quite careful
Also, keep in mind that different fibers respond best to different blocking methods. You can wet-block acrylic yarn, but you should spray-block cashmere. The weight of the yarn and the density of your knitted fabric matter as well. Hope that helps!