Thanks for writing in.
Dienne 35 is hormone based contraceptive
it may cause pigmentation as a side effect.
But pigmentation can occur due to variety of reason like like lichen planus
, post inflammatory,amyloidoisis etc.
Proper examination is required for diagnosis of the cause.
I encourage you take visit to a qualified dermatologist
for examination and proper treatment.
Visit a dermatologist for some clinic based procedure like chemical peeling and laser
Hope this helps.