you can buy "snag catchers" at the LQS or Joann's. They are like your seam ripper but instead of having a sharp point they have a little hook with a clasp. You can go from the front near the snag or back and pust it thru the hole where the snag is. Then you catch the snag in the hook close the clasp and gently pull the snag back thru. You might even be able to move the bump with it if the bump is not attached to the fabric. I would agree with doing a small applique as has been suggested. It is a way of "making the quilt her own".