I can't see the photo well enough. But is it possible? Sure! We all take the risk everytime we walk outside and come back in to our grow area without sanitizing ourselves or the clothes we wore.
Also bringing in outside air without filtration.. or if you ever set your plant outside or in a open window, then yes you risk it being pollinated. Is it ever possible... absolutely!
Hard to tell in this photo. The calyxces will start filling with seeds, you will have little ball sacks just waiting to burst open. That's when you know you've been pollinated.
Goodluck, I'm hoping you haven't accidentally been pollinated.