The views expressed by me are for educational purposes only and do not establish a doctor patient relationship.
Thanks for your question.
Based on your description and good response to benadryl this does seem to be hive or allergic reaction.
This is not a std or HIv as the description does not fit.
Hence, you should not worry about these conditions.
Please rate Good or Excellent Service, if you are satisfied with our conversation and do not have any further question, so that I get rewarded for my time & effort. Thank you!
Please bookmark my profile for asking further questions! This is the link to my profile: http://www.justanswer.com/medical/expert-mysticdoc/