Typical treatment for a scar like this is subcision with filler/botox and something for the texture weather a acid peel or erbium laser resurfacing once the area is raised.
I have seen good results with botox (used as a spacer) and subcision, then worry about the texture as stated above. This area moves (muscles) so botox is necessary.
Best to see a scar specialist and they will explain in detail. Botox can be used to decrease muscle movement. An experienced specialist will subcise gently with dilute Botox, namely microinjections to break up the scar tissue. This is very different from cosmetic Botox (2-3 injections). If you find the correct specialist, they will break up the scars with microneedling manually. Then inject 4-8 units of Botox (or more) depending on your muscle movement. Another viable option is dermal filling with gentle subcision. The plane has to be exact as there are blood vessels that run deep in this area. Best to see in person, as dynamic movements must be taken into consideration. Static photos give some idea, dynamic assessment is Gold Standard.
When the swelling goes down, Could be a few days, to a week. Depends on your body.
I cannot give you a percentage of improvement, it depends on the skill of your doctor (injecting, subcising) and how you heal. Filler will give it lift and acid peels or erbium will work on the surface texture. It will take some time and healing. Dermastamp can break up the scar tissue. You will get improvement.
Peels or laser help with this. It's from the way you healed and were stitched up. Subcision will lift the valley part then you can work on texture.
@Ricky007xxWhat are you asking? Your doctor says you will not have white after the filler. She/ he is performing the procedure. So get treated if you wish. Were talking filler here under a recent scar revision not a white scar.