1st session update:
After three weeks the hairs started falling off on their own. Thin armpit hairs are mostly gone. The thick ones are stubborn so they grew back.
On my second session:
A reminder for those who are/will be undergoing this treatment. As much as possible DO NOT SHAVE YOUR ARMPITS, especially a week before your appointment. I was rescheduled because of this, so I had to wait two more weeks before I can have my second session. Just endure the 1 1/2 month's worth of underarm hair so you can keep on track. :-)
One thing I have noticed during the treatment was that I felt more discomfort on my left underarm, which has fewer but thicker hairs, than on my right underarm which has more but thinner strands.
It has been 3 weeks since my second treatment and most of the hairs have already fallen off. It feels gooood to have clean underarms again! They said I should wait until the hairs fall off on their own so I'm really fighting the urge to pluck the remaining ones. :-P
I'll make an update regarding my third session next time. I really hope I'll get my "permanent" hairless underarms soon! :-D