Blister on shaft , after condom use?

Hello,
Over the past several months I have slept with several women. Each time wearing a condom for both oral and vaginal sex. Last night while showering I noticed a small bump on the upper shaft just an inch below the penis head. The part where there is a dark ring around(every guy has it.). The bump caused no pain so I am suprised i noticed it. Like the fool I am..I popped it. Some white fluid came out. Still no pain really. At this point it is a bit inflamed(from popping) and is much more visible. Is it possible this is herpes(or any other std for that matter) even though I used a condom?? I understand condoms only reduce risk by 30% of catching herpes.But the condom does cover my shaft and head. Especially the very top of my shaft where this thing is located. I know there is other skin exposed such as my pubic area and testicles but this is at the top of my shaft. Is it possible I have herpes there even after wearing a condom?? Please write back soon, I extremely distraught. Thanks, Ted.