Just last week had to deal with a similar issue. I put some liquid OxiClean (maybe a tablespoon or so) in a coffee cup full of clear water, put the affected part of the quilt on a white towel with a color catcher between the two, and used a white bath cloth to gently, gently, gently brush the stain with OxiClean/water solution.. This quilt was already quilted and waiting for me to put a sleeve on so I could enter it in a show.
I left it on the bed where it was lying when I was working on it--towel still under it--turned on the ceiling fan and let it dry over night. Nothing is left of the stain.
In my case, it was bad dog! froggyintexas