Hi.. Thanks for the query.. As per your complain swelling over the half of face along with swollen lip seems to be most probably due to allergic reaction to some unknown allergen leading to Angioedema of face and lips.. It can be due to causes like allergy to any food or medication while other causes can be skin cosmetics, poison ivy etc.. You should consult an Allergist and get evaluated and a thorough clinical evaluation and investigation like RAST test, Patch test etc can help in ruling out the cause and treatment can be done accordingly.. As of now you can take anti allergics like Levocetrizine or benadryl to reduce the swelling and do cool compresses over the swelling.. You can also consult an Emergency room and they can give injectable steroids to reduce swelling faster.. Hope this helps.. Regards.