Hairline lowering surgery, what can I do about scar and hair re growth. (photos)

You can always consider a hair transplant surgery to disguise the scar from a forehead reduction surgery.  Sometimes SMP (Scalp MicroPigmentation) may be used in combination with a hair transplant surgery.

The appearance of your scars is common after hairline lowering surgery, especially if there is a tight closure. Placing single hair grafts in and in front of the scar will give your hairline a more natural appearance. Consult a hair transplant specialist to get advice with regards to this procedure,
Dr. Robert Jones

Hairline lowering with scalp advancement will always leave a scar. The appearance can be improved with hairline variegation and transplantation to mask the appearance of the scar and the straight hairline. Choose your hair transplant surgeon carefully as it is not an easy fix. 

I'm sorry you had temporary hair loss and scarring after your hairline lowering procedure. You can still achieve a very nice result if micro grafts are placed in the hairline and any adjacent thin hair. Consult with a transplant specialist.

The scarring you have may be the result of a surgical wound that was closed too tight which is known to form scars like you have. A transplant in front of this will create a more natural and softer hairline and the buried scars can be treated with Scalp Micropigmentation (see below)