Ankles,groin,anal And Certain Areas On Torso Itch With A Few

Ankles,groin,anal and certain areas on torso itch with a few red spots(small pimple size) have had unprotected sex in past three weeks, also have been taking clindamycin after dental work. Stopped taking antibiotic last week when itching started thought it was either just dry skin or maybe meds, started meds a day ago and itching has intensified greatly could this be std ?