Any ideas of what's going to be used on my child's cut? When can they use glu?

Depends. The need to close a laceration depends on the size, depth, and location of the cut. The purpose of sutures (stitches), staples, or glue is to pull the edges of the cut together to allow it to heal with less risk of scarring and infection. A type of medical 'super glue' can be used on cuts in areas such as the scalp and in areas that don't get a lot of pulling.