One of my friends works for a dr's office that does laser hair removal. When the office first got the machine, my friend offered a bunch of us a deal if we would be guinea pigs. I had my facial hair done while others had their underarms, legs and bikini lines done. We had mixed results. For me, personally, the worst of it is gone. I think it's been over a year now since the last time I've had hair on my upper lip and chin. There is no sign of regrowth. I still have some hair problems, but I am attributing that to genetics and possibly a medical issue. As far as I'm concerned, the treatment was a success and I do not regret the money I spent on it. Some other friends did not have the same success that I did. Your hair and skin color plays a part how well the treatment goes. Those with lighter hair did not have the same positive results as those of us with darker hair. Also, the darker the skin color, the more careful the person treating you has to be with the laser. So be REALLY sure whoever is working with you knows what they are doing.
Please, please, please do your research on this. I had one session with a different office who used a machine that ended up burning my face and leaving some fairly unattractive marks. Fortunately, they healed and there's no scarring. The machine my dr's office uses is SO much better. The process can be a bit painful. My face got really red after a treatment, not unlike what happens after you've had a waxing. However, the redness went down very quickly - I think in about 10 - 15 minutes. That reaction will be different for everyone.
If you have questions, I'll be more than happy to answer them. Feel free to PM me.