Good Morning and welcome! I am Dr. Loretta, a licensed veterinarian and I am happy to answer your question.
there are a couple things that this mass could be. One is a lipoma which is a fatty tumor that is benign and harmless. If you can get your fingers all around this, this may be the cause. This could also be an inflamed Lymph node due to either trauma or an injury causing this node to be inflammed. It is a good sign that Melrose is not lame or that this mass is not painful. If anything, it may be scar tissue form an injury that you may not have been aware of.
You are doing all the right things by hosing this and it may help to apply colld compresses to this area to help decrease this mass. In most cases, this is a benign lesion that will not harm Melrose and would not require treatment.
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, ***** *****
Thank you so much, Katy, 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 am sure Melrose will do well with you caring for her.
Have a wonderful day!