Recently my rat terrier developed a boil on her but.  This is the second time.  The first time it got rather large, but went away the day I was about to take her to the vet.

At the time I had thought she got bit by a bug and got a reaction.

This second time she developed it in the same place, so it was obviously not a bug bite.

I asked my wife’s cousin who runs a shelter and found that dogs get, “anal gland infections.”

Usually if you leave them the dog will just lick them until they pop and it will heal up.  If it won’t pop then you can take it to a vet and they will drain it for a small charge. 

Our dogs infection went away on it’s own the second time as well.   I was glad to find this a common thing. I was getting worried my dog developed a tumor and would cause me a huge vet bill.