I have been having recurrent hair loss since i was 18 (now 23). It starts with a pimple which doesn’t itch but the area is tender with fine hairs at the bottom of my head also around the hairline.
Infected cysts can cause hair loss (sometimes temporary and sometimes permanent). Your history is too sketchy to make much sense out of it for me. You need to have a doctor examine these ‘pimples’ to see if this is acne or something else.