Will my hair grow back fully after Trichotillomania?

You may have permanent loss of hair in that area which requires excision of the area or hair transplantation once you are no longer pulling out the hair. See a very experienced 

Some amount of hair loss may be permanent in trichotillomania, especially if it has been going on for many years. The only way to promote hair growth is to stop the pulling. Repeated pulling damages hair follicles, causes inflammation in the skin and triggers scar tissue to develop.Treatments to promote hair growth (such as minoxidil) and treatments to stop inflammation are often used. But the main treatment is to stop the pulling.  Assistance from a psychologist or psychiatrist is often needed to address the underlying issues that caused the pulling in the first place.