The answer to that question is not so simple, it is variable. I just ended my 7 year tongue piercing. I remember watching Malcolm in the Middle, where Malcolm just got his tongue pierced and said “After a week, I can just take it out anytime and no-one will know the difference”.
Here is my personal experience…
I had my tongue pierced early in 2004. At the time I was working at a University in Australia. About 6 months later, while I was at work, I was eating a chicken burger and then CRUNCH, I thought I just chewed on a rock. But the ball on the end of my tongue barbell had fallen out and I had just chewed on it. I was the only person at work and couldn’t leave to put my piercing back together (i.e. find a mirror), and being a relative newbie at piercings I wasn’t yet talented enough to put it back on without looking. After about 2 hours I was relieved from work, went straight to the bathroom and…
Tolerated some horrendous pain to push the barbell back through again. I ended up pushing through scar tissue… there was blood everywhere and it stung all day.
That was about 6.5 years ago.
Now I live in Japan and work as a teacher. Schools do not tolerate any visible piercings or tattoos. I got sick of wearing retainers, they are quite short and since the bottom isn’t screwed on, it was always falling off.
Finally I decided that it was serving no purpose and I got good value out of it. So I left the barbell out.
One night later… I pushed a barbell through and although a little tight, it went back in fine. I left it out again.
The second night, the barbell would only go about halfway through, beyond that felt like some pretty solid scar tissue.
So that’s it, I’m now piercing free. If you knew me during my Uni days, I got this piercing in my second year of Uni the morning after a massive party we had in our house at Toormina. I work up sleeping face down in the carport and decided, hey I’ll get my tongue pierced!
So 6 months, it took only 2 hours to start closing up.
7 years, it took 2 days to close up.
It’s funny, it closed up about 2 weeks ago and I still do the habitual movements of attempting to play with the piercing. I never put the metal between my teeth, but I would flip my tongue over and put the bottom ball between my lips. Now all I feel is this weird ring of thick skin where it has healed over.