Is it permissible for a bald person to undergo hair transplantation on his head to rid himself of the harm inflicted upon him by some people, especially if he is young?

It is permissible to take hair from the back of the head and plant it in the affected area, because this falls under the category of restoring what is missing and removing a defect, and not under the category of beautification or adding to what Allah’s creation. This is evidenced by the story of the bald man whose hair Allah restored to him.