I got my tongue pierced about 13 years ago. It wasn't all the rage at the time. I saw one guy with it and thought, "wow. I want that." I should mentioned that my Dad forbid me from getting tattoos and said he would not pay for my college education if I got any. So, I thought he never said anything about piercing.
Anyway, there was no pain involved in the actual piercing. People don't realize this, but we have very few nerve endings in the middle of our tongue. I came home stuck a popsicle on my tongue until it melted. I had swelling that night and was fine afterward. I used the listerine religiously and brushed my tongue ring 2 times a day. I know everyone has all of the horror stories about chipped teeth and infection, but I had mine for over ten years and that never happened. In that time, I never removed that thing once. I bit down on it about three times during the first two years and decided that I needed a shorter bar. By the way, shorter bars make them less detectable.
Alot of people did not notice I had one. I didn't stick it out of mouth and I spoke normally. I had normal jobs and a lot of my employers did not know about it. I got other piercings during this time and my father was more upset with the eyebrow.
"People can see that one."
As for your daughter, she disobeyed you and should not be allowed to keep it after the healing has occured. They close fairly fast. Tell her that she can make that decision when she is an adult. You can come up with whatever punishment you deem necessary.