20 days back i went for movie and in that theatre no one was around me. So for 40minutes i mastrubated with my hand. now i am getting fear of hiv because my penis was outside for 40min if some of hiv viruses or if someone ejaculated before me around that place...if that virus come in contact to my penis along with air. So i am really scared help me.... do i need hiv testing ? Will be i at risk ?