text: is it possible to reduce the size of a zit overnight?   before going to bed try swabbing with hydrogen peroxide, let it dry then put on a little bit of antibiotic ointment, if it's still red in the morning, put a little dab of hydrocortizone cream. try that twice a day. usually works within 24 hrs. and the hydrocortizone cream at least makes the redness go away, so it's less visible until the antibiotic ointment works. also, i use tea tree oil and it's gone in about 5 hrs. you can buy all thos products over the counter. try health food store for tea tree oil. good luck.