Hi thanks for your question.
Though chances of pregnancy
are very less,but as precautionary measures you can take unwanted 72,as uptill now only 48 hours have passed.There is no difference between I Pill and unwanted 72 as for emergency contraception
The side effects of unwanted 72 include vaginal bleeding,which may vary from light to heavy.Breast tenderness.You may also experience some nausea
and vomiiting.The lump on your labia majora
most probably could be a boil (infected hair follicle) for which you need systemic antibiotics.
Hope this answers your question.