Please take your dog to the vet as soon as you can. Blessings - Blu
Welcome to the forum....From your description, it sounds as if your dog is very ill! You may be wasting precious time looking for answers on the internet...I suggest you get her to her Vet ASAP....These issues can only be resolved by a Professional...Good luck and let us know what you find out...Hope you can get in quickly.....Karla
Sorry to hear your dog is not well. Especially due to the age, you don't mention her breed, these may be signs that something isn't right. Without seeing it, the lump may be a swollen lymph gland, beginning of an infection, etc.
I suggest you take her to the Vet for an exam, blood work and a dental exam. If she has not been in fir a while, I suggest you take in a fresh stool sample, if you can get one, to be checked.
No way to tell what may be going on but your Vet might be able to narrow it down and suggest treatment.
Good luck!