the black triangles usually don't resolve, in another words, gums don't grow back. if it truly was due to trauma and irritation, it may refill but you'll know in about a week or so after it happened. if it's still there, you may have to go back to your dentist and have them bulk up the filling a bit to fill the space. injection of dermal fillers also help fill in the gap although temporary.
for a 24 yo male, with a healthy bite, i would rec a 6 unit. if you have a bite where your anteriors are not that functional (which maybe a different issue on it's own) you can get away with a 4 unit.
if the reason your gum has receded is because there is decay around the margin of the crown, you need to have the crown replaced. if it is a gum issue and there is no decay, just recession around an otherwise healthy alive tooth, you maybe able to have a gum-graft to replace the lost soft tissue/gum.
dental bonding or porcelain veneers will both give you beautiful results. there are pros and cons to each so explore them wisely.
form the picture it seems like it's either a paralyzed muscle on your right or an over excited muscle on your left and i would think a surgeon would be able to help you out. consult either an oral surgeon or a facial plastic surgeon. i'm sure you can get some improvement if not a perfect result.
