STDs from single Handjob

Hello, Please help. I am really concerned. What is the Likelihood of catching STDs? 7 days ago, for the 1st time in 4 years, I went and hand a body scrub and handjob at a massage parlor. Dunno if they washed hands, they had a small cup with the scrub (dunno if it was used before with someone else). they massaged my scrotum and penis. Now 5 days later I have pain in groin, some tiny red dots all around my scrotum (saw a doctor says it's folliculitis) - I got waxed a week before. there is urethra pain have a dark half inch rash on my buttock (dunno if it's been there from before). I'm worried about STD's. Please help!

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