Where to get a longer stud for my lip?

ebay and piercing parlours that are online will have them just look them up in your area as you should know, 4 days obviously isnt enough for any piercing to heal, and you really should wait at least 3 months before changing thenm but if the skin is swallowing up the piercing, youll need to as leaving them in will just cause a horrible indent that wont heal as for your school you obviously shoudnt have got facial piercings if your school doesnt allow them because you cant be taking them in and out when youve just got them done, unless you want an infection so either put in studs if they allow them put in clear labreats (plastic studs) if they allow them keep in mind even the clear ones are noticable or take them out and actually wait untill your out of school