Could be an allergic reaction to something you ate.
Could be small cold sores.
Could be impetigo.
Too many could be's. lol
You'll need to see a doctor in order to figure that one out.
From the symptoms it can be due to an allergic reaction or food allergy. Do not use any cosmetic products at the sites. You can apply some calamine lotion at the rash as it will help in soothing the skin. You can take some OTC oral antihistamine medications like Benadryl or Claritin and see if it helps.
For mild-moderate symptoms a weak steroid may be used. Also use good quality moisturizers and Vaseline on your lips.
If the symptoms persist then get it evaluated from a dermatologist.
It is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided. For exact diagnosis, you are requested to consult your doctor. I sincerely hope that helps. Take care and please do keep me posted on how you are doing.