Hi KSM Sundaram.
Thanks for the query.
Usually evening rise of temperature can be seen in many conditions like Tuberculosis
, Connective tissue
disorders, allergic reaction
This needs to be investigated well by her Rheumatologist
to find presence of Connective tissue disorders especially if she has arthritis or joint pains.
Paracetamol will be useful to control fever but not very safe for long term use because it can cause kidney damage.
Kindly get her evaluated for Tuberculosis by sputum test if she has cough, Mantoux skin test by Dermatologist
, also if she has any small swellings in the neck, Lymphoma needs to be ruled out.
Wishing good health.