All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
It is Islamically permissible to implant the hair of the head as this is not considered to be among the attaching of artificial hair with natural hair that is forbidden as mentioned in the Hadeeth reported by Al-Bukhari and Muslim; the text of which is as follows: “Allaah has cursed the woman who joins the hair and the woman to whom the hair is joined...."
This is not considered to be changing the Creation of Allaah, because it is bringing back what Allaah, The Most-High, has created at the beginning. It is a method of treatment which is permissible as it is an appropriate implantation [implanting the hair in its original place].
The evidence about this is that 'Abdur-Rahmaan Ibn Tarfah narrated that his grandfather Arfajah Ibn Sa’d had his nose cut on the day of Kulab (a battle which took place at the time of the Pre-Islamic Era of Ignorance), so he took a nose made of silver and attached it so his nose started to stink, so the Prophet "ordered him to replace it with a golden nose". [Abu Daawood]
Therefore, it is permissible for a bald person (or partially bald) to implant hair be it his own hair, or somebody else’s hair. However, it is preferable for him to implant his own hair rather than implanting that of someone else.
For more benefit, please refer to Fataawa 129818 and 142901.
Allaah Knows best.