It’s great that you went for a test and that they were all negative. If one of these STI would have passed to you in 2013 it would have certainly shown up on a test you had done in 2015.
It is common for us to see people in the STI clinic with the symptoms you have described. Most of the time we find that it is something that is non-STI related like a yeast infection, a skin condition etc…
Diagnosing skin conditions can always be a challenge as much of the time there is no test available to see what is causing the problem.
If you’re not happy I would recommend getting a second opinion from another doctor. If they are unsure what is causing the problem they can always refer you to a skin specialist (dermatologist) to get their opinion.
If your still in jail and only have access to the same doctor you could always put in a health care request when the symptoms are there worst and see if they have a different opinion.
We know it can be very frustrating when you are trying to work out what is causing this problem for you. We are unable to diagnose conditions online as we would need to see it as well as look at your medical history.
Please leave a comment to let us know if this answers your question or if you need more information.
For other readers, please feel free to leave a comment, or let us know if this was helpful.