12 y.o. Not neutered long hair chihuahua male, 15 lbs. Willy.

In January of this year he had an anal gland abscess on his left side and we opted to remove the anal sac. I awoke to him today in a bloody mess from his rear end and took him straight to the vet. The vet said it’s another anal sac ruptured abscess ( on the left operated side.). The dog is in recovery and has a drain after flushing out and abx. Vet said he saw a hard mass deep in that abscesses side and biopsied it and we won’t know until Friday 8/23 what the cytology says.

How can this happen again if he has no anal gland on that side? Has any vet or vet tech encountered this before? Is it the small mass that did this to my poor dog?

Thank you in advance.