Cotton has "memory". When quilting the needle pushes the woven threads out of the way. After she removed the stitches the cotton fibers held the same position they were in when the quilting thread filled that "hole" which isn't really a hole at all but the space made in the weave of the fabric from the needle going in. Drying it probably won't make a difference. You need to wet the quilt in order for the cotton to give up it's memory. You can try spritzing with a water bottle but washing and drying should make those areas close up entirely and the weave of the fabric will return to its original look.