Since about 4 monthso on the left side of my dog's anus(sorry i dont really know the specific terms) there is a lump or it is swollen. He can poop normally with no problem , and he acts healthy as usual. He is about 8 years old . I took some pictures , can you people help me know what is this?
Note : its pictures of my dog's *** with a lump next to it.
http://imgur.com/a/1Sxg5#0