Am in to be worried about hiv? detailed answer pleasse?

i was at a playground and i picked up a straw in water near a water fountain. i have no knowledge if the straw was used by a hiv infected person or had any hiv infected blood on it. i had bandaged non bleeding cut that i got 4 days ago on my hands/fingers and some kind of very small broken blister or peeled skin that wasnt bleeding. im scared thinking that i could be infected with hiv like this. what if there was blood and it got in me, would there be any risk at all? if there isn't, then how do i convince myself im fine? would u worry if u were me? D: