Flesh eating tumor???

Question
Hello, i went on vacation and had my cousin take care of my pet rat. I came back two weeks later to find her very malnourished and i was VERY upset. Not only that, but she has a tumor on her left front leg almost on her neck but not quite. My dad said its normal but it looked blackish and today i am so upset i just went to feed her and you can literally see right inside! i am very scared and it happened so fast!!! i have no idea what this could be and i have had rats my whole life and have never seen this! i am really concerned upset and scared for her. Do you have any idea what is happening?? the 'tumor' is almost the size of a golf ball and the whole is about half inch. I am really scared, could this be a bite? It literally looks like its eating away at her flesh and the outside is like a black scab with some fur on it. PLEASEEEEE HELP!!! thank you

Answer
Sounds more like its an abscess or an abscessed tumor.  Have you tried to clean it out?

If it came up fast and opened, its an abscess. You can easily clean this yourself by using some saline solution and cotton balls. Try to clean it, let me know if you get pus and what color it is. It may be green or yellow and it may have an odor. Apply neosporin on it.

Take a photo of it please. The black is necrotic tissue, dead skin.
You can attach the photo here or email me at sandyscrittercity@yahoo.com

Take a look at my website and the tumor photos and the photos of abscesses and let me know if they compare to your rats.  
Do you have a vet?  You may not need one if its an abscess but if its a tumor that has abscessed it needs removed or she can get really sick from the bacteria.   I am hoping its just an abscess since it came up out of the blue.  I will know more when I see the photos.

http://www.sandyscrittercity.com/

look up tumors and abscesses on my site.