How Long Does It Take Before a 5-month Course of Accutane Takes Effect?

A typical Accutane course (though brand name no longer is available in US, generic isotretinoin medications remain so) takes at least 5 months, sometimes 7-8 months depending on the clinical judgement of your board-certified dermatologist. The clinical benefit can be seen in 4 weeks though some may not see significant benefit until 2-3 months into the therapy. Procedures such as laser treatment or chemical peel should be deferred at least 6 months if not longer after completion of Accutane to minimize complication.

Accutane (Isotretinoin) is by far our most effective treatment for severe, resistant or persistent acne. A typical course is 5 months, though in some severe or slow responding patients, 1-2 months more (rarely) may be required.
I tell my patients not to expect much other than dryness and peeling in the first month. By 2 months, most people are seeing a definite improvement, by 3 months a significant improvement, and by 4 months most are clear or nearly clear. It is important to take the full 5 months (with a goal of 120-150mg of isotretinoin per kg of body weight)-- studies show this decreases your chance of having a relapse.
I don't know what procedure you are referencing (it's not mentioned in the question)-- but as a general rule, any procedure that would disrupt/damage your skin barrier should be delayed for 6-12 months. More aggressive procedures such as medium to deep chemical peels, laser resurfacing or surgical procedures should be delayed at least 12 months.

Within one month of starting Accutane, changes of acne clearance has started to begin.  Some will see over the 5 months, a total melting away of the acne condition, some will see it get much worse before it starts to melt away and the third group will notice that the acne waxes and wanes for the entire 5 months.I hope this is helpful.Steve Greene MD, Advanced Dermatology and Laser Institute of Seattle