Welcome and thanks for posting your query to HCM.
After reading your query I can make out that the swelling is ruled out for the possibility of cysts, boils
IN your query you have not told since how long you have the problem or any associated symptom. Many a times there appears a trivial swelling without any obvious cause and most of the times it is due to simple infections. Do not try to pinch or squeeze the swelling. Your doctor has wisely prescribed you a course of antibiotics. You just wait and watch, most of the swelling subsides by its own.
With good health wishes
Dr. Sanjay Kumar Kanodia