Hi Sump...., Thanks for writing in to Healthcare Magic! Postinor is levonorgestrel used for morning after pill emergency contraception. It would not affect your ability to conceive in future, it causes short term hormonal changes only. The pimples are due to collection of fatty secretions, local acid formation and bacterial infection which leads to formation of comedones-the black heads. Best method is to wash the face with lukewarm water and soap(you can use medicated soaps like-savlon/dettol) but not the face wash or other very soft preparation. You should dry the face by wiping it out with thick cotton towel, rub with pressure so that any retained greasy content get expelled from the skin pores. Then apply the cream Benzoyl peroxide(Pernox/Persol 2.5% gel) twice a day for 45days. Avoid fattening foods, fried foods and fast foods for best results. If you have any further query please let me know I would try to answer it for you. Wish you a great health!