My Boyfriend Is 18 And 5ft 10. Yesterday Morning He

my boyfriend is 18 and 5ft 10. Yesterday morning he found a small bump on his butthole. Today is has swelled to about the size of the tip of his pinky and it covers 3/4 of his butthole. He said he did force a poop yesterday but it was in the afternoon. The bump is not red, does not itch and does not burn. It does not bleed, instead it is causing some discomfort when he sits down and he says it hurts all the time. He thinks it is a hernia or that vein has popped out. Can someone explain to ne what it is, or could be, and what are the solutions to fix it?