About a month ago I had unprotected sex with my ex who has been highly sexually active(i supposed). I have a discolored blotchy scaly type rash on the back of my hand which is barely visible. Its look black, not red. Its seems to be under skin instead of raised. No fever or sore throat or swollen lymph nodes. I've think I've had joint pain but no muscle aches. Yesterday I've had diarrhea and I'm vomited the other day but I think it was because of something I ate. I'm going to get tested buy I wanted to know if this is conclusive to ars?