Zingers=OUCH!

I am a Dental Hygienist and I work at an office that offers Zoom whitening. I am not good at remembering to use bleach trays and I have always wanted to try zoom. I also wanted to know how to conduct a zoom whitening session and provide the protective covering for the gum tissue. Another dental hygienist that I work with wanted to try zoom also, but we decided that I would go first (and we only had time for one of us that day). We did all of the protective coverings: lip protector and retractor, guaze in the cheeks, cotton rolls under the lips, and liquid damn to cover every piece of the gums that could be showing. Looking in the mirror, there was no red showing, just teeth. She then put the bleach gel on and put the light on. I did the first 15 minute session, no problem. We suctioned the bleach gel off, checked the protective barrier and then reapplied the bleach for session 2. About 10 minutes through the 2nd session, I felt my first "zing". It really suprised me, because it came out of no where. I then did about 2 more minutes and felt multiple zingers. I can handle pain to an extent, but I've never felt anything like this zinger before. I took the light off and got all the bleach and barrier off. I rinsed my mouth out. My teeth were not very sensitive to cold, hot, or air. BUT for 2 hours afterwards, I continued to have the "zingers". There was no warning that I was about to feel one, it was just a total suprise everytime! I took some of the relief gel home to put in my bleach trays, but I didn't feel like it help me much. After a couple hours I was able to eat dinner and had maybe 2 zingers the whole time. I even was able to eat ice cream later. Through out the night, my teeth were sore and I woke up multiple times. The next day, my teeth were still sore, but not really sensitive. As far as the shade change goes, there was a little difference, but not much. I think I went up 1 shade. I wish that it didn't hurt so bad, so that I could have finished the 2nd session and completed a 3rd, because I think that I would have really noticed a difference then. Was it worth it? For me, no. I didn't have that much in shade difference and it was extremely painful. I wish there was a better way to explain the zingers, but those of you who have felt them, know that they are horrible! Whenever someone at he office asks me about zoom, I am now able to tell them about my experience and leave it up to them to decide if they want to do it or not.