herpes usually is a red bump and turns into a blister or sore, if you start getting lots of headaches or swollen glands i would get it checked out.
syphilis will give you a sore a few months after getting it but its followed by rashes and shit on your feet and palms or cock.
most stds cause burning, discharges or are accompanied with flu symptons like nausea, fatigue, cramps, diarhea, etc...