Good Morning and welcome! I am Dr. Loretta, a licensed veterinarian and I am happy to answer your question.
Most likley this mass is a tumor that has ulcerated and is filling this area with blood. This may or may not be a benign tumor but it is important for Monty that your vet open this up, debride this area and biopsy it to know for sure. In most cases, these are benign masses and removal is curative. It is best for Monty's quality of life, to remove this and know for sure.
Does that make sense to you?
Please let me know if you have ANY other questions. My goal is to give you 100% satisfaction and if you are not yet satisfied, please REPLY so I can clarify for you.
Sincerely, XXXXX XXXXX
Thank you so much, Valerie, for your kind rating. It is very much appreciated! Even though you have rated, we can still communicate. If you have other questions, please Reply. I am always happy to help. I will send you a follow up in a few days to see how Monty is doing and if I can answer any other questions.
Have a wonderful day!