I Have Had Unprotected Sex About 2 Weeks Ago... I

I have had unprotected sex about 2 weeks ago... I am 16 and after a couple of days a red spot appeared on my chest... it was big like ring worm pictures... I have a cold and have spoke a lot with a sore throat...does this mean I have hiv? When should I get a test? The rash has spread now with a couple small rings but the rest are like small spots with dry skin... there are not too many but I think it's spreading on my bbody.. what should I do?