Clearz ultra & clearz max. Whole night?

My doctor suggested me to use both Clearz ultra & clearz max But he said,"Discontinue the course of Max cream once it complete Then use the Clearz ultra(Arbutin & Kojic ) cream after completion of Clearz ultra cream My doctor suggested the Max cream to be used in alternative days in night time for 15 days & give break for 15 days 1) can we use the Clearz ultra(Kojic +Arbutin) for life long? 2) Can we repeat the Max cream in every regular intervals once pigment occur again? 3) Can we use Clearz ultra in night times for long term? Is Kojic acid & Arbutin safe for life long apply for dark spots ? 4)can we apply clearz max cream just one hour or whole night ? sometimes I use to sleep without wash the Max cream,does it effect if apply for whole night? Please help me for above 4 questions, Looking forward for your reply