I've used pinless peepers on a couple of my birds including a rooster. Regarding my rooster, after I removed them after two months, it seemed that skin grew around the plastic and when I pulled them out of his nares, there was minor bleeding from small torn tissue. I applied a tiny bit of Neosporin in each nare and left it. It eventually healed up.
I couldnt use the peepers on him again because his nares were enlarged due to the peepers.
The lumps that you see might be swollen tissue that had grown in or around the peepers inside the nares. I suspect the swelling may go down in time. As long as your chicken is eating and drinking, acting like a chicken should, I wouldnt worry about it.
