Have you had any preemptive discussions about this at all? Around here you have to phone gp at 8.30 and wait for about 10-15 mins on hold and then tell the receptionist what the problem is and they decide if you are allowed to have an appointment. So for a teenager to do this themselves is pretty much impossible.
i am worried about teenager looking up online and stressing themselves when they just need to speak to a nurse /doctor for reassurance but that is near enough impossible these days.
I remember being able to call the doctor receptionist myself at any time and ask for an appointment without giving any information at all. But all these things are gate keeper.