Lump under my old roosters beak

[Countryprincess716]

Hi! I have a 8 year old free range rooster that is acting lively, eating, drinking, but seems little listless. I know he is dealing w mites a little but I noticed he has a huge lump under beak! He’s definitely been acting like an old man, standing w eyes closed, picking at the mites more, etc but I want to try and help this guy!
My flock is 150 and no others have these symptoms! Thanks! What could this be and how to treat it!?

 

[Eggcessive]

Do you see anything inside his beak in the floor of his mouth? Look for signs of canker, a bad smelling yellow to gray infection inside the beak. Pictures are welcome. He might have a cyst or tumor, or even an abscess if he has been scratching it. Is the lump keeping him from eating normally? Have you added any new birds to your flock recently?