I have a rash but no swollen lymph nodes. can we say is it early symptom of hiv aids?

No: If you are worried, get tested.

HIV: If you have had unprotected sex and are worried that you may have been exposed to an std including HIV then you should go either to your local health department or to your pcp and be tested for all relevant diseases. Please do this asap since if you have gotten HIV disease, the earlier the diagnosis and institution of therapy, the better.