If it is inflamed I would definitely take her to the vet. Older dogs can definitely get 'lumpy' with benign cysts but the inflammation is worrisome. Hopefully everything will be fine!
The wisest thing to do is go to the vet and get the lumps needle-biopsied. Get them properly checked out. If one of them is a bad one, it needs to come off straight away.
A needle-biopsy doesn't take long, maybe about 5 minutes, is not exactly the nicest fun thing to do for your dog, but isn't exactly painful -just a little uncomfortable for her. It doesn't need anesthetic, and you can be with her to help hold her still while the vet does it. She will have to stay very still though for a few minutes, so a veterinary nurse or vet tech will probably help to hold her still.