When you sew anything that ends with a point at the edge of the block, you should have a quarter inch of the "background" of the block between the point and the raw edge of the block. In other words, there should be a seam allowance at the end of the point. How did you lose that seam allowance - did you trim the block or was it that way when you finished sewing it?
I agree, a picture would help. If you don't know how to post a picture, there are 2 threads in the "Help" section of the forum, and they're permanently attached to the top of the page.