Thanks for your patience.
I can understand your concern.
You seem to having angioedema and urticaria.
Angioedema is an extension of urticaria(hives) where usually the soft tissues of the face are affected. Such as in your case.
It may be idiopathic or may have a variety of causative factors, there is a n exhaustive list available but to tell you the truth its really difficult to pin point one thing.
the best thing to do is to start prompt treatment for immediate relief.
tablet fexofenadine 180 mg orally once a day is the medicine I would recommend for atleast a couple of weeks. you may also need to extend it for 3 months to get the allergic response under control.
also you can apply cortisone cream on the rash to help it settle. It has to be applied twice a day till there is a rash
It can be caused by foods, medications, pollen, house dust etc.
I would advise avoiding fish, milk, nuts for 15 days would be a good idea and see if it further helps you.
A word of caution, since in angioedema, there is a swelling of the soft tissues, it would be best to be alert for any symptoms of difficulty in breathing or diffficulty in swallowing( if the swelling extends to the tissues of the food pipe and the wind pipe), you will to rush to the ER then, since it requires urgent attention then.
These are my suggestions, I hope they really help to address your concern. Please let me know if you have any queries. I will be happy to answer them , till you get an answer to all your queries.
Hope my recommendations are helpful.