Hello Doc, About A Month Ago I Had Protected Sex
Most likely yeast infection not herpes or warts.
Detailed Answer:
Hello dear, welcome to "Ask a doctor service" . I read your query and here is my advice.
Herpes or warts can be transmitted by skin to skin contact so even though you may have used a condom you may have been infected by skin to skin contact.
Herpes has more possibility to be transmitted while the person has rash outbreaks. If one doesn't have the rash it is less likely to be transmitted.
About the rash you had it is less likely to be warts or herpes because it went away next day by using nystatin acetonide and was painless . It is more likely that it could have been a candida infection (yeast infection) .
Hope I have answered the question.
Let me know if I can assist you further.