Thanks for your query
I think, from your history, you are suffering from angioedema
and urticaria as your lip swelling
does not decrease with antibiotic therapy and itching is associated with it. So in all probability it is an allergic manifestation. I advise you to take anti-histaminics in the form of desloratadine or fexofenadine
tablets along with an H2 blocker like ranitidine
along with your antibiotic therapy and look for the improvement. I think it will reduce by these medications. Also i should ask you to go for serum c1 estarase estimation and consult an allergist for further management.