Post shingles terrible pain

Female 77 is suffering from very bad post shingles pain. Skin lesions have dried up although visible and discoloured but feels as if she is being lashed with burning water! She cannot sleep as a result, went to the doctor who preescribed amitriptyline. She took it for 2 days and became more depressed as it reminded her of a previous occasion in her life when a lot of anti depressants were prescribed. She has lost a lot of vitality and muscle tone during this illness and is not at all herself. She can normally tolerate a lot of pain without complaint but it keeps her awake at night. She has to keep her limbs out of bed at night as she is so hot but then becomes very chilled. Please help as she appears to be going downhill. Thank you.