Hi I Have Some Tiny Spots On My Penis Head,

hi i have some tiny spots on my penis head, the head is also quite discoloured and has a fish/ salty smell. i have occassional pains in my testicles as well but nothing serious to constitute a symptom. am worried this could be an std? no other symptoms, but i had unprotected oral sex with a stranger almost a year ago, neither of us climaxed so no fluids were exchanged so i dont know