Geri - there are lots of different ways to handle this one.
First - how "shy" are you?? If the square finishes 6 1/4" I would say leave it - pin a piece of paper to it saying 6 1/4" or 1/4" small so you remember a year or more from now - whenever you go to piece it together. In many situations applique is cut down to 1/8-3/16" seam allowance. If that scares you - put another row of stitching inside the seam allowance to strengthen.
If your block is smaller than that, what does the outside edge look like? Many of these blocks have borders on them and "fixing" yours to make in larger could simply mean removing outer edge and cutting that one wider. The alternative is to add a 3/4" strip all the way around - I would make sure to
cut it at least 1" because you have to remember you will be making what's there 1/4" smaller all the way around. Many DJ blocks have extra thin borders all the way around. In fact, I'm sure Jane Stickle must have run into this 'shy' problem herself here and there. When you examine her blocks carefully you will notice some with very narrow borders all the way around, and some with only one or two!
Remake ONLY as a last resort...
of course that being said we are our worst critics! ....just try to remember it is not only your quilt, but each is one block in the midst of 224 others!
Gus