Suggest Treatment For Black Marks On Face

Hi Doctor, Recently I consulted a doctor as I got white patches in my right feet and pimples in my face. He prescribed me A-cn soap & DOXRID tablet for pimples and eldem oil & eldem tablet for my white patches. But, after applying the soap for a week my face become almost dark so, I consulted him again to check why my face has become dark. He said it would be due to taking medicine for both problems at same time & he asked to replace a-cn soap with derma dew and asked to stop eldem tablet. For the past two days am applying derma dew. But I don t see any change in my black marks :( . it looks like my face is burnt. Could you please help me will my face turns normal, if i continue derma ? Please help me am afraid