Not plastic/acrylic, its too porous for a new piercing. You can probably get glass though. Glass at smaller sizes is very fragile though. Bioplast is another option but its not as clear as glass.
it is a plastic piece you put in to retain your navel piercing
No. Retainers are made of plastic which is not suitable for initial piercing. Initial piercing should always be done with a titanium barbell.
it is a plastic piece you put in to retain your navel piercing
Most of the time its just clear plastic jewelery.
yes that would b ok
Bioplast or PTFE the size is not one size fits all you need to tailor the piece to the piercing. See your piercer for detailed help.
You don't. The only real thing that you can do to "hide" it would be to wear a clear retainer, but this will be an obvious rod of clear plastic through your lip. The only other alternative would be to leave it out, and with it new, the piercing will shrink up super quick.
Possibly. It depends on the person. If you need to remove it for a particular reason consider buying a retainer - clear plastic (PTFE) bars or rings which are less noticeable but will make sure your piercing stays open.
Yes. Ask your piercer for one. Most places have glass retainers in stock.
No because retainer pierces are plastic which isn't pure at all for the body. Your initial piercing is almost always sterling silver and it will take about a month or so depending on how quickly and fully your lip has healed.
I do not know that is why I asked the question. The retainer ring has a plastic or acrylic frame around it.
How long a piercing takes to close up depends on the gauge of the piercing but mostly it depends on the individual. All I can give you is anecdotal evidence; I removed my 14g lip piercing which was 18 months old and was unable to re-open the hole without re-piercing just two days later. If you want to keep the piercing open but need it to go unnoticed (say, for a job interview or a particular event) consider using a piercing retainer, these are clear plastic bars which are almost invisible when worn.