Can Plastic Surgeons Widen a Narrow Forehead?

Generally severe facial deficits are addressed by craniofacial surgeons in childhood.  Performing elective craniofacial surgery is a very difficult road.  Depending on your issues, there may be simpler means to help you with your appearance.

When asking about 'widening a forehead', one has to know more specifics about what that means or what your objectives are.  Forehead augmentation can be done through a scalp incision to build out the forehead with onlay material but it usually lies on the bone within the anterior temporal lines. Building out or widening a forehead behind the temporal lines is problematic as that requires lifting up part of the temporalis muscle, which will can easily be done but almost always results in muscle atrophy later potentially exposing the edges of the built out area if they are not perfectly smooth. This is what I would call widening of the forehead.  Augmentation can be done of the temporal hollows, although that would not normally be considered part of the forehead.

I would consider the opposite principles we use to make a wide or high forehead lower and narrower. This could only work if the forehead had a lot of laxity in the side to side direction. It could involve incisions in the temples and might require the removal of some hair within the temples. . The scars should be hidden within the hair. 

That being said, I have never done this exact operation for your purposes. Consider resubmitting this question with pictures that clearly show your concern.