Umm, I think perhaps you sould see a doctor if you have purple lips and are feeling light headed.
Are you currently taking an anticoagulant, such as Warfarin or Coumadin? I understand that some get purple toes, perhaps fingers when they are taking an anticoagulant, and that is a bad sign that needs medical attention.
I have not read anywhere about anyone getting purple lips as a side effect, but I suppose it is possible if the anticoagulant is causing the blood clotting to get way too low, which can cause bruises anywhere.