What is the white gooey stuff on an open wound?

Several things...: It may be slough, which is white blood cells and debris in the wound. It may be exudate, it may be pus, it may be left over wound medication. You need to have the wound looked at to determine what the white "gooey" stuff is.

Two most likely.: If white and gooey is more on the runny side and associated with increased redness, increased pain, swelling, and/or odor - it could be puss from infection. If the consistency is more like hard jello, without the other features, then it is most likely what is commonly referred to as "slough". Adherent slough should be removed as it increases risk of infection due to high degrees of bacteria in it.