What Causes Red Spot On The Head Of Penis?

I.have one red spot on the head of my penis..its not painful when I touch it...it did have some skin peel off earlier today...I have had protected vaginal sex but unprotected oral sex...I went to the doctor I'm waiting on the std and blood test to come back...he said it didn't look like a classic case of anything like herpes or warts but I'm super stressed and worried...how.can I.live if I have an.std...?