As we age, the bony structure of our skull can change which can show up as hollows, furrows and grooves on the face. A very common area where this occurs is on the forehead and frown area. With repeated movement of the muscles of expression, lines can form and become quite deep. Shallow static lines and dynamic lines respond well to Botox. Some lines can become so deep that they will not respond to botulinum toxin and therefore require dermal fillers to help lift these.