Hope you are doing great.
The history which you have provided is a bit vague but still the possibility of insect bite reaction could be considered.
Whatever it is you should consult a dermatologist
At home you should rub some ice on it and apply calamine
lotion for its cooling and soothing effect. If the area is raw you should apply an antibiotic ointment till you see the doctor.
If it really hurts, you can take antihistamine tablets.
Hope this helps you.
Bye and take care