Greetings.
Are you exposed to the unsafe sex?
Since when was the mass?
Did that appear suddenly?
Did it precede some violent sex?
Dr. Arun
Dear Paul,
This must have been hematoma or seroma, which popped off or red bump of herpes. This (later one) can be a sign or symptom of herpes, although not very common. Read here;
http://www.mayoclinic.com/health/genital-herpes/DS00179/DSECTION=2
The majority of people with herpes don't show any symptoms. Then transmission is not related with the outbreaks. Without any symptoms or outbreaks, disease can be transmitted. Since you have no problem presently, it may not be helpful to consult urologist although it may be prudent to consult infectious disease specialist (since your partner has herpes) and get tested for sexually transmitted disease.
Hope this helps. Your follow up questions are welcome.
Doctor (MD)
MBBS, MS (General Surgery), Post-doctoral Fellowship in Sports Medicine