(female) I just noticed this past week that I have a bald spot in one area of my head, the top left. The area is smooth and tender. (Tenderness may be a result of the products I’ve been applying to stimulate growth.) I am assuming that this baldness occurred after a no-lye chemical relaxer was applied, since I now vaguely remember a patch of hair coming out at that time. How can I know what caused this area to become bald and when will the hair grow back if it will? By the way it looks, it seems that nothing is happening.
Smooth skin suggests a burn (it could be other conditions, but with your memory of history a burn sounds likely). See a good dermatologist and you may get some good insights into the bald spot. If it will grow back (not a third degree burn or one that killed the hair follicles) it may grow back in 3-6 months.