Firstly, your boyfriend needs to have an ultrasound
of the scrotal area urgently to rule out testicular torsion
, which has a similar picture. Testicular torsion is a condition in which the testis twists on itself and swells up and becomes painful. It is common after sexual intercourse. If that is the case then he will have to undergo surgery to correct the torsion (urgently), else the affected testis will become functionless. If the ultrasound shows only cyst
, then getting it aspirated (with all aseptic precautions else it will get infected) is alright and not going to affect his potency. Either way cysts dont lead to cancer. If there is no cyst or torsion, then he just needs to take the antibiotics for a little longer.