Hi,thanks for your question.
The bump you are mentioning could be a bug bite
as the bump is surrounded by a red oval inflamatory responce to a bug bite.
The yellowish discharge could be puss due to superadded bacterail infection.
You need antibiotics, antihisitiminics, and analgesic
anti inflammatory (pain killer) drugs
Consultation with a Physician is encouraged.
Hope,this answers your question.