Talk to Dermatologist on Skin Issue

My skin is second to none when it is normal. in past my skin tone is little dark because I don't take any care of it .but before approximately 2.5years I take care of my skin very much. it also given very good results. now tone is white, but some times my skin behaved very colour converted into yellow dark which made its look unhealthy, and my oily skin also produced oil, I don't wash my face more than twice in a day, this oil is also helpful for me when my skin normal because on that time my skin is smooth bright like a glass skin because then it lighten my skin. now oil produce but my skin look dark, black head, redness under eye, little little dark spots not many but they look worst in oily skin. with this dark circles are also available ?.those are more worst made my face. I don't used in my life any type of product like moisturezir , toner, serum ,cleanser, sunscreen,home remedies. so why this happened with my skin help me please.