I performed a consultation for a piercee whose initial jewelry in her nipple piercing was too short:
I got my nipple pierced last night and I think it maybe too small its 14g and 9/16". I am doing the sea salt soaks. Just concerned thats the bar is too small.
The bar is definitely too short for your build! You must visit your piercer ASAP to have it changed for a longer bar. Hopefully the jewelry is internally threaded or the piercer has an insertion taper that will screw onto the existing bar to avoid passing threads through your freshly pierced tissue. See below.
Throughout healing, there should be a millimeter or two of the post showing on each side when your nipple is relaxed out to its widest dimension.
Only after you are fully healed should you consider wearing a bar snug enough that the balls are right up against the tissue.
Here's the information I suggest for aftercare: http://piercingbible.com/piercing-care
Below is a section from The Piercing Bible about embedded jewelry:
When you fail to change out jewelry that is too short, it can become embedded. It is much easer to prevent this from happening than to treat it after it does. If your jewelry is starting to sink into your tissue, see your piercer for a longer piece right away.
Tongue and lip jewelry normally nest (sink a millimeter or two) into the soft oral tissues, but if more than half of the ball has disappeared into your piercing or the skin appears to be growing over your jewelry, visit your piercer as soon as possible. Oral tis- sue regenerates extremely quickly, and jewelry can end up embedded overnight. If you cannot immediately get to your piercer for help, use elevation, rest, ice, and over-the- counter anti-inflammatory medication to minimize the symptoms until you are able to get your jewelry changed.
In the unfortunate event that the tissue completely grows over the jewelry and you or your piercer cannot push it back through the surface, you must seek medical care. A small incision will be made (generally under local anesthesia) to allow for removal of your unintentional implant. If you want to preserve the hole, obtain jewelry of the proper size beforehand, as it might be possible to insert it after the embedded piece has been liberated.
Don't delay--this is a very serious matter!