What Is The Treatment For Swollen Lips?

Hi, I woke this morning (4am) with a severe swelling of the lips. I immediately thought it was an allergic reaction but had eaten for 6 hours before so slightly puzzled. Went to the hospital and was given IV anti-histamine that seemed to work quickly.

The nurse also took my blood and the Dr has now explained that my blood count is low, and could be the result of bleeding from somewhere. Could it be an ulcer and if so is the lip swelling related and not an allergic reaction?

Many thanks for your time.