I agree with Feline Fanatic. Your best bet is to go back and quilt closer on that color. I had that happen on a table runner (3 actually) that I was making for my nieces. The star and focal point of the runner wrinkled horribly when washed and I'm not sure any of them own an iron. I put one on the back of a chair and stared at it for a couple of days before I decided that I had nothing to lose and quilted the inside of the star with diminishing star shapes inside. Washed it again and it worked!