It might possibly be fowl pox, but if it hasn't gotten morse or if more bumps haven't appeared, it's probably not pox.
My hens had dry pox, and they had bumps that turned black all over their face, comb, and wattles. It cleared up on its own after a few weeks. Someone described dry fowl pox in chickens as being like chicken pox in humans.... if that makes sense.
Wet pox gets in their throats and mouths and other areas. It can cause respiratory symptoms. This eye bump isn't that, thankfully.