I'm 50 and have suffered with acne all my life. Although it is somewhat under control now, I still get cystic acne (about 1 a month). I also have blackheads on my nose and some are larger and stubborn - they'll sometimes turn into zits but just never go away. My derm suggest I try isotretinoin for 1 month (30mg) but I've read that it's only effective if taken for several months. Any thoughts on taking isotretinoin for only 30 days? Thanks.