I don't know how your stud can just fall out unless you're wearing a fishtail labret. It depends on how long the jewelry has been out for. If it was recent, they can just put in new sterilized jewelry. If it has started to heal, they'll have to repierce it. You may or may not have to pay for that.
you should use a stud
If it's a vertical Labret piercing then it's a curved barbell, if it's a standard lip piercing it can be a labret stud or a ring.
Stud as in a normal earing stud? Just grab the butterfly clip and pull the stud out. Stud as in a lip stud? Firmly grasp the flat back and twist the end off.
a Lip Ring or Stud .. haha i love you
Depends which part of your lip but they usually say stud at first because of the swelling but they usually ask if you wanted a ring when healed.
look on the inside of your lip, and the outside, and stick it straight in based on the angle of the holes.
Absolutely NOT!
any body can get a lip piercing as long if its a unisex or male stud or jewelry
Unscrew the top ball, remove jewellery.
LABRET this is a stud in your lip
Get a new ring, or if it's just that rings are uncomfortable for you, get a stud.
If the jewellery is sized correctly to account for swelling and you are following your aftercare guide you were provided with, the stud should be OK. If you have swelling causing the stud to embed it's self into your lip then you need to get in to see your piercer asap and get a longer stud put in till you clear the swelling stage of the healing process.