Improving traumatic forehead scars
The bottom line is that the appearance and texture of the scar can be improved even if it is many years old. There are many options including laser resurfacing and surgical scar revisions. An examination with a specialist in facial plastic surgery would help to give you the appropriate options. Good luck in your a
Even old scars can be enhanced
A variety of laser or energy based treatments can be done to improve the appearance of your scar. There are even treatments - fractional ablative and fractional non-ablative - that have been shown to improve the areas that lack pigment and appear white. I would think you have a very good chance of achieving significant improvement in your scar. It can not be erased but it can be improved. I would encourage you to seek a consultation with a physician who is experienced in using lasers to treat scars.