Hi, Thanks for writing to us. Firstly the cause of pigmentation has to be ruled out. Dark arms could be due to tanning, lichen planus pigmentosus, Post inflammatory hyperpigmentation etc. As diagnosis can be made only after seeing the lesinos, so i would advise that you visit a qualified dermatologist and be compliant to the treatment advised. More or less all dermatologists prescribe similar treatment as we follow a standard treamtent guidline. So changing doctors wont help. The basic treatment plan in pigmentation is Use of sunscreen( mandatory) and complete sun protection Use of pigmentation reducing creams if not much response is seen with topical creams, peels and lasers might be required. Hope this helped you to some extent. Take care