Does the risk reduce if the needles was in its cover ? Am I at risk at all ?
This is not a risk for HIV. HIV is transmitted in very specific ways. Sharing IV drug needles is one of them as well as unprotected vaginal or anal sex. But sharing IV drug needles is different than stepping on a needle. The end of a used needle is exposed to air which inactivates any hiv virus if there was any. Injecting is different than sticking yourself. You had zero risk for HIV from what you describe.