No - I think investigating an allergy that causes swelling of the mouth/face is very important. Can you have a good think about everything she has eaten or drunk in the hours before this happened? Make a list - anything new? And make sure you have antihistamines in the house.
Think about things like jams, juice drinks, fruit with edible skins like plums/peaches/nectarines, any kind of nuts, anything with colouring.
No, you have those instincts there for a reason. If she is allergic to something, that something is still present and still affecting her as her reaction is getting worse.
I think the lack of concern from the Dr and nurse is reassuring from the pov of it's not a serious reaction, but it's a reaction nonetheless and is continuing so of course you should pursue an explanation.
I would get her seen today. Do you have a walk in centre you can take her to? If gp wont give you emergency appointment today or if you can get to walk in centre then I would take her back to A&E. Any swelling on the face that is as you describe should be investigated immediately as it has the potential to spread and block thge airways. You arent over reacting and A&E staff wont think so either.
i agree with nellie - i wouldn't wait either , waiting just means another night of worry for you & an uncomfortable night for your dd , i have a very bad allergy to fish , last year after a walk along the beach my face swelled up so bad my eyes almost closed over , 1 phone call to gp & i was put on a course of steroids , piriton is good but i doubt it will be strong enough to help your dd's swelling . hope she is ok -good luck x
if you are worried then yes you should go to the walk in centre , piriton is good for itching etc as its an antihistamine , but swelling is different , as other posters have said swelling could effect her breathing therefore is a real concern , how old is your dd ? imo she might need a course of steroids to stop the swelling & while you are there ask the gp to organise allergy testing if possible . x