I am really sorry to hear about what you have been through. I would recommend you to consult a skin - cosmetic surgery specialist.
The treatments vary from melanin blocking agents combined with topical medications such as Retin A which causes the body to exfoliate the skin to rid the body of the hyperpigmentation while prohibiting new melanin production to laser treatments. The treatments wholly depend upon your needs and skin type.
For standard non-hormone induced hyperpigmentations Hydroquinone usually reduces or removes hyperpigmentations very effectively. It is a bleaching agent. Also always use sunscreen/sunblock as dark areas on exposure to sunlight turn darker still. For some patients with severe hyperpigmentation,surgical and cosmetic intervention may help.
Wearing sunscreen and avoiding the use of abrasive cleansers and cosmetics for the face may help. Get enough sleep and eat a balanced diet everyday.
It would be advisable to consult a skin specialist for your symptoms and a proper clinical examination.
Let us know if you need any other information and post us on how you are doing.
Thankyou, I'm already following most of your advice re: sleep, diet, sunscreen (though these scars don't see the light of day much) and will make and an appointment to see a specialist.