I've never had a guines pig w/ mites/mange before. I think you should take her to the vet and get some meds because it wn't clear up on its own if that is what it is.
When we first got out poodle 7 yrs ago she had the mange; it takes forever for them to get over...we had to go back and forth to the vet so many times...
goodluck w/ your guinea pig!
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