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There are a number of causes of swelling of the cheek like that. It may or may not be a tooth infection.
I would recommend that he should visit the A & E to be evaluated and be seen if it really is a tooth infection or not. The ER doctor may also prescribe antibiotics in case if it is a tooth infection.
Therefore the next best thing to do here is for him to be seen either by a GP or in the emergency and then move on after that if the GP or the emergency doctor suggests a tooth infection.
An NHS number is not absolutely necessary to see a GP or to go to the emergency.
So he can still book an appointment with the GP and go to the emergency.
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