Roosters anal area inflamation

[cockyrocky]

I noticed that behind my roosters tail feathers near his picky area it is hard bulging and very very red and feathers lost. He is a gentle rooster what is wrong with him???? Please help. I have been applying neosprin and started him on an antibiotic, Hopefully its not cancer!

 

[Chickiemama1010]

I dont know but a picture might help