On a visit to vets just before xmas my daughter's nearly 9 year old Gsd castrated male (check up on trocoxil ) he also has CDRM or DM as now called.mentioned that he had been after his anal region ,was his glands full did they need emptying?.Vet examined him and found a 1-1 1/2 inch lesion by side of anal opening .He thinks that dog has had a abcess burst ,very clean .no meds .no cleaning .will check him in a fortnight ! We are now very worried that it is something worse.What are the chances that an abcess is all it is ? Have no knowledge on this.