I get quite a few questions about individuals with scars and whether or not we can transplant into them. The quick answer is yes, but with a lower graft survival rate (let’s say 50% of the grafts will grow).
When you cut the skin, you change the physiology of the components that it is made up of when it heals back. Hence why you see a change in the texture and colour of the skin in the form of a scar. However, although you change the “landscape” of an area of skin including the loss of hair in a given area, the vital requirements (blood vessles etc) for hair to grow in a scar is still there but to a lesser degree than normal skin.
If you take a plant from a warmer climate and were to uproot them and put them into a similar climate but perhaps slightly colder with less than ideal conditions for that specific type of plant or tree you can make an educated guess that some plants would survive and others would not of the same species. This is the same for hair when we transplant grafts into a scar. Some will survive and some will not.
If you have had an accident, facelift, scarring of any sorts – provided it is in an acceptable area of where hair should be – a hair transplant into the scar is the best and truly – the only way with current technology to mask a scar and make it blend in with normal skin when the hair is at a slightly longer length, thus breaking up the scar.
An example of this is seen below of different scars from my own head. One is a before photo of scarring and the other is where hair is used to break up the scar and reduce the visibility of it.