If head of his penis was entered in a way that you could not see it, there is a slight risk due to possible precum. Your risk is there but not significant because his status is not known and strong chances are, he may not be an HIV+.
It is good that you do have concerns about unprotected sex.. only a condom is the best friend of a woman, not her boy friend. Next time, unprotected sex only between you and your mutually committed monogamous partner, for rest of the world, no contact without a protection.
You may get yourself tested for HIV Duo 4th generation after 4 weeks of the exposure, collect your conclusive report and move on with your life
PEP is usually recommended when the risk is significant, that is unprotected vaginal or anal sex with a confirmed HIV+ partner. However you should consult a doctor specializing in infectious diseases to evaluate your risk and decide
I would barely call this a risk. First of all you don't know his status, and chances are he is HIV-. Second you did not have prolonged unprotected intercourse with him leading to ejaculation. If you are concerned, maybe you both should get tested with a 4th generation DUO test. If that comes back negative on him, you are essentially in the clear. If you want to get tested, do it after 1 month. When it comes back negative accept those results.