Hi. This may be a constitutional problem in your Case.. Don't worry, you can try applying hair growth peptide lotions or minoxidil for about three to six months and see if it helps. Repeated shaving and with age the growth may become regular. Otherwise transplantation from scalp hair is the ultimate option. See a qualified dermatologist near you or send in further queries to follow up chat. Hope this helps. Warm regards Dr Govind Suresh Mittal.