You have stretched the area, and will have to shrink a lot more of it. Try more areas around the edge of the bulge. Only heat an area once. after that, move over, going around the bulge, then working your way in.
They have those shrinking discs too, but from the pictures and description, it's too stretched for that.

http://www.youtube.com/watch?v=F6rPdaZQ7_c