there is usually some swelling with a new piercing and that will go down which sometimes corrects the look, although at four weeks, you should be past most of that. you could also try wearing a stud with either a longer post or a larger stud ornament on it.
your main guide is how does it feel? if it is tender from the stud digging in, you will want to change jewelry or it can delay complete healing. if you can clean it ok and it feels ok, you are fine. if you don't like how it looks, give it a bit more time and then get a new stud.
- Rae