Well the jewellery should still be in the piercing, you never remove jewellery from an infected piercing unless it's the jewellery that caused the issue in the first place. Mall bought jewellery is junk and will cause reactions that will often look like and infection. Make sure you have the original jewellery in the piercing and leave it in until your situation has improved.
She can still keep her navel piercing in.
Yes it isn't uncommon. The piercing may not have jewellery in it however dirt, bacteria and other nasty things can still enter the old piercing site and cause it to abscess Navel piercing sites need to be cleaned regardless of there being jewellery in the piercing or not.
If it is still infected then it has not healed. If generic antiseptics have not worked then it is advisable to see a physician.
Hopefully, it is not infected. The skin of the area should be clear and healed. If it is still red, bumpy, bloody or anything else abnormal, continue to wash it twice a day and make sure to see a doctor to make sure it isn't infected.
3 to 6 months, depending on how it looks. If after 3 it looks nice and has no puss or discharge you can change it. If it still looks red or infected, I would wait another month or two.
i got my piercing when i was 13, it healed straight away and im now 16 and me growing hasn affected it.
Where the bar usually is yes. If you feel like there's still a bar when u take the ring out, then that is fine, otherwise i would get it checked out.
Yes. Of course, you still want to take really good care of your piercing while taking the antibiotics.
That depends. If you lost the piercing by somehow ripping it out and the tissue is still scarred than no, but as long as the navel is not damaged it should be fine. Try talking to someone at your local tattoo or piercing parlor, they should know.
I believe that it is the same anywhere in the US. 16 with parent/guarding consent, 18 without it. That goes for any piercings, except ear lobes which can be done with a gun (the only piercing that is done with a gun). But you'll still need parental consent.
Any good piercer won't allow you to get a hoop. If your piercer gives you the option then he/she doesn't really know what they are talking about and you need to find a piercer who will ONLY pierced you with a barbell. Hoops can get infected easier and migrate quicker. Barbells still have a huge risk of getting infected, because it is a navel piercing and they do get infected quite easily unless properly taken care of, but hoops can get infected much easier.
It is possible, but actually rare. Even people that dont have a very defined navel "lip" can still get a navel piercing; it is what you call getting a shallow piercing, meaning there is not much skin to pierce through. I have seen successful healing with shallow piercings, and I have also seen some that are not so successful. Talk to your piercer about whether or not it is a good idea for you to get one.