oral melanoma

My 13 year old dog Nina has oral melanoma.  The tumor was removed 6 months ago.  It came back within 4 months.  The oncologist and my vet both agree that it cannot be removed again.  It is growing very quickly.  She is on pain meds and just finished an antibiotic.  She is doing very well and doesn't act like anything is wrong right now.  Her breath is VERY bad due to the tumor breaking down and bleeding sometimes.  I am feeding her dog food that has been watered down and mushy.  I have taken a Qtip and cleaned it somewhat, but I am wondering if there is any more I can do.  I can only imagine how bad it must taste for her.  I was going to use some mouthwash on a cotton ball, but not sure if that would hurt her or cause it to bleed.  

[Cliff Redford, DVM]

Sorry to hear about this diagnosis.
Oral melanoma is a locally agressive tumor and therefore often returns to the spot it was originally in.
Very little can be done to reduce the odour, other then what you are doing. Your vet may have access to an oral rinse you can add to the water that will help with the odour. Human mouthwash contains alcohol in it and therefore will sting.