[Doll]

Actually, going from hot to cold does more than improve circulation: it actually stimulates collagen production! Many women use this same idea in the shower, bouncing their breasts under the water, switching from hot to cold water, back and forth for a few minutes, to keep their breasts looking firm and perky! I actually do it myself. I don't think I'd enjoy the blow dryer as much as I enjoy the shower water, but I can't see why it shouldn't help.

Although if you do it in the shower, it'll help your skin all over, not just your breasts (giggidy).