thank you for such a detailed description of the bumps. It is accurate and certainly points to what is most likely a 'staphylococcal' infection. These are caused by a common bacteria. It would be wise to take her to the doctor. This is following the usual pattern of 'recurrence' which means, it appears, gets better, then appears elsewhere. It might progress onto an abscess
, which is a collection of pus, if neglected. So , no panic, but do make sure your doctor has a look.
Dr Antony Robert