Hello,
Unexplained swelling of the lip and cheeks without any predisposing disease is frequently caused by allergies. An allergic reaction can occur suddenly, even in a person with no previous history of allergy.This swelling of the lip and cheeks is called angioedema.It is the rapid swelling (edema) of the dermis, subcutaneous tissue, mucosa and submucosal tissues.Symptoms include swelling of any body part which appears suddenly and comes and goes.
Diagnosis is by clinical examination and complete blood tests,electrolytes and renal function tests.Treatment is by antihistaminics and steroids. Take antihistaminics like Claritin or Benadryl and apply calamine lotion and a mild steroid cream like dermacort on the rashes. If the symptoms persist then pls consult a dermatologist.
Hope it helps.Take care and pls do keep me posted on how you are doing or if you have any additional doubts.Kind regards.
I would think of ABCD Air Borne Contact dermatitis possibily to plants,or ACD Allergic Contact Dermatitis to like nickel in jewellery.If you have a preexisting allergy in family more chances of such acute reaction.Steroids may be indicated,keep in touch with your physician.