Depending on the size and cause of the “dents”, sometimes, dermal fillers can add volume under the skin to plump the area back out. If it was tissue damage, the tissue is normally fibrous, and can feel a little more tender when the needle, or cannula goes through it.
Please not that not all injectors fill the forehead. This is considered to be a “higher risk” area to treat with dermal fillers, as there are major arteries that supply blood to the eyes here. If you visit this link: https://cityskin.com.au/team/ it tells you what practitioner treats the forehead with dermal fillers at Cityskin.
Alternativley, some of the cityskin clinics also provide Clear and Brillant. This laser is a fractional laser that causes a “fraction” of a wound in the skin, to help stimulate and produce collagen and elastin. This could be used alone, or used in conjunction with dermal fillers. This link will take you to FAQ about Clear and Brillant offered at Cityskin. https://cityskin.com.au/laser-treatments-cityskin/clear-and-brilliant-laser/