A dent in the skin of the forehead may be caused by acne or by regularly manipulating your face into expressions that cause an indentation, known as a worry line, between your eyebrows. Although nothing can be done about many of these marks, you can take steps to treat the dent or dents in your forehead so they become much less noticeable.
Wash your face regularly with an exfoliating cleanser to remove dead skin cells and reveal newer skin. The newer skin contains more collagen and is therefore fuller. Be patient. It may take many washes before you begin to see the dent getting shallower.
Apply liquid or cream scar treatment medication to the area daily. This will help heal any skin damage that is causing the indentation.
Schedule a consultation with a plastic surgeon. Discuss injectable fillers, like synthetic collagen, that may be more successful in plumping up the depressed skin in the dent, giving you nearly instant gratification.