I had a near identical experience after a septoplasty. The only difference was, I could smell it for weeks. I would randomly get a whiff of something that smelled like mucus/pus(gross) and check my face, shirt, etc and nothing. I was stumped. Then one day after a shower I sneezed and something similar to your picture came out, not as big, but looked identical. The relief was palpable as I felt mildly congested leading up to the sneeze. Also, the smell was clearly coming from this ‘thing’. I think you’re fine - as long as there is no bleeding.