Suggest Treatment For Depigmentation

Good day I went to see a dematologist about a month ago for the pigmentation on my skin. He prescribed depigmentation cream for it. After a few day into the treatment, my pigmentation has lighten but, my skin was a little red. I then contact him by email and he prescribed Isotrex for my skin. I am not sure what the purpose is for the Isotrex. He suggested I used the Isotrex every night and the pigmentation cream atleast twice a week in the evening. Before a started the process, I gave my skin a rest untill the redness went away. I just started a week ago with this process because my pigmentation seems a little darker after stoping the pigmentation cream. Now my question you Dr is, do you suggest I just continue the process and can you please let me know what the Isotrex are for. I also saw white patched around my pigmentation after the redness went away. Will this go away? Thanks