The procedure is very fast: it takes no more than 3 minutes for each side. I shave the morning of the procedure and the deodorant is removed right before the procedure. There is pain involved, very similar to the "snapping rubber band" pain I've read about. But the pain gets less intense for each treatment, and it is tolerable because the procedure is so short. If I were getting a larger area treated, I think I would need a mini break! There is also a strong jet of cold air blown over the treated area during the process which helps numb the area some. For me, the pain of the laser is much less than the pain of waxing. Be prepared for a mild smell of burnt hair during the procedure. Right after the procedure deodorant can be reapplied immediately. I have had only minimal discomfort (I can't even describe it as pain) for the next hour or so after treatment. No pain meds or other aftercare is needed.
As for results, halfway through treatment, I have about an 80% reduction in hair growth. The hairs that are present are baby-like, so from a distance you really can't see them. Be prepared that the hair loss does not happen quickly. For me, my hair actually got stiffer and thicker for the first two weeks after the first treatment. I was initially upset, thinking the treatment didn't take. But 2-3 weeks later the hairs started falling out on their own (gentle exfoliating during a shower helped quicken that process). Also, I have had no scarring or discoloration. The darkening of the armpit skin associated with previous shaving has almost disappeared.
I wish I had done this procedure earlier because it is so nice not having to think about shaving my underarm area every few days. But I am glad I waited until technology offered a safer alternative for those of us with dark skin tones. I am planning to have my bikini area done next.