Walk around your lawn in these or another type of cleated shoe. Mow again and fertilize. I suggest a fertilizer that releases nitrogen slowly. Too much nitrogen absorbed too quickly promotes good top growth but not much root and side growth. And those of us with bald spots in the lawn want side growth.
Bare spots are an invitation to weeds.
There are other good ratios available. Ask your nurseryman to help you determine which is best for your needs. The first number of the fertilizer formula represents nitrogen, the second phosphorus and the third potassium, which promotes root growth. When the lawn is rapidly growing, mow weekly and mow at the proper height. The recommended height for St. Augustine is 2 to 3 inches.