I had unprotected sex with two girls about two months ago. About 3 weeks after I noticed a small rash on my inner thigh. After scratching the rash it began to spread. Now the rash has an outer layer of itching bumbs where the inner part looks like dried up skin. I noticed improvement when I stopped scratching with the help of lanacane. There is no itching on my penis or gentals and I have no other symptoms other than the rash on my upper thigh ( the part that is in contact with genitals). Could this be a STD?