Brief Answer:
Take antibiotic for a week.

Detailed Answer:
Hello
Thanks for your query ,based on the facts that you have posted it appears that you have popped a cyst that you had on shaft of the penis resulting into a sore wound and you are worried it to be STD or Herpes .

I shall be happy if you can post me few more details to help me in making comments on your problem.
1) Since how long you has this cyst on shaft of the penis ?
2) Did you have unprotected sex with unknown woman in recent past ?

Based on your statement it seems to be a ulcer over shaft of the penis after the cyst has been popped up .The possibility of STD or Herpes can be be considered only if you have unprotected sex with unknown woman .

You need to take broad spectrum antibiotic like Cefotaxime along with anti inflammatory drug like Diclofenac twice daily along with topical antibiotic ointment like Neosporin twice daily.

Ensure to wash your genitals with warm water twice daily

Ensure to avoid sexual encounters till it heals up completely.

Hope I have answered your query ,please feel free to ask if you have more questions , I shall be happy to help you .
Thanks and Regards.
Dr.Patil.

---

Brief Answer:
You need not do STD tests .

Detailed Answer:
Hello
Thanks for follow up .Since yu had sex with your girl friend who is known to you .There is no fear of STD and may not doe STD tets .

Take antibiotics form Pharmacy .

You will need prescription from your family Physician .

Thanks an Regards
Dr.Patil.

---

Brief Answer:
It is not Herpes .

Detailed Answer:
Hello
Thanks for follow up .

Clinically it does not look like Herpes .

Thanks and Regards.
Dr.Patil.

---