Had vacuum with ds #1, I had been pushing for almost 4 hours and his head had been right there the whole time, I was squating, standing, on my side, on my back, ect. and he was still in about the same spot.
I didn't think either of us were hurt too badly from it, I did tear, but not too bad and he did have that poofy spot on the top of his head for a few hours, but no visible brusing.
I think mostly I was just so tired, I had been laboring for more than 30 hours and it was the next night and I just wanted that baby out and to go to bed. I can remember saying "just get it out, just get it out" and that was when my doc suggested we try the vacuum, especially since his head was right there.