Hi, I can understand your concern for the problem macular amyloidosis in back. In macular amyloidosis there is overactivity of melanocytes at dermal region. Melanocytes are the color producing cells of skin which causes superficial and deep pigmentation which may appear as pigmentation in Lichen amyloidosis. The most important part in treatment is by sun protection by all measures. Eat healthy diet containing lot of Vitamin A and Vitamin C. Do not try applying over the counter products as these can further aggravate the situation. Protect yourself form direct sunlight. Use a good sunscreen on exposed area for 2-3 times and drink plenty of liquids everyday. Lightening agents such as Kojic acid or azelaic acid or Hydroquinone cream application which you can use under dermatological guidance. As the pigmentation is deep in nature so even lasers are not effective in the treatment of amyloidosis. It may help a bit but can not remove the pigmentation completely. All the best.