Hairline lowering/forehead reduction surgery scars problem? (Photo)

See your doctor for a follow up on what your doctor may recommend.  There are few options:  You can transplant hairs to the scar as well as have Scalp MicroPigmentation (SMP) to diminish the hypopigmentation on the scar.

I suggest you have a scar excision and use a technique that we described many years ago where hair follicles buried under the skin grow through and in front of the the incision. It may e necessary to use a few micrografts if necessary at a later date.

It might be worth revising the entire scar with a 2 layered closure so there is no tension on the skin itself. There should be no attempt to make multiple small sawtooth incisions if they were done before since you have dark skin. If scars widen again, hair transplants and micropigmentation could work.