I did the same thing a few days ago, but I like your fix a whole lot better than mine (ripping & redoing).

Love your cheerful and bright quilt.. The birthmark comment was precious, and I like the triangle. If it bothers you, I agree with many - add random triangles. And if you are worried about fraying, cover the seams with decorative rick rack and maybe a small applique inside the triangle as your GD's trademark.

I like it how it is, Pretty.