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Where are the lumps?
Could you take a picture of them and post it here?
How old is your cat?
Is she indoor only or does she go outside?
The first thing I would want to rule out is a flea allergy. Flea allergy dermatitis usually shows up as small bumps/ scabs on the neck and back. If she's not on a flea preventative, I would start some Frontline or Advantage or Revolution.
Here's some good information on fleas:
The other thing I would want to rule out is Hyperthyroidism. This can lead to increased vocalization, weight loss, hair loss, increased appetite and skin lesions.
Here is a nice set of links on how to work up and treat Hyperthyroidism in cats:
I hope this helps, let me know if you have any other questions.