Acne or  pimples... Due to hormonal changes..Oily skin causes it...Common in adolescent age...May occur in adults also.. Food like Oily foods, ice cream, chocolate and sweets increase it.. Treatment depends on the grade of pimples or acne..So, please  send photos by direct online consultation as it's a must to see which grade of pimples or acne for accurate diagnosis and treatment.

hi .. dark spots usually occur due to reasons like sun exposure, from the history that u have mentioned since u have already tried home remedies i would advise that you visit the dermatologist so that he can physicially examine you and advise u on further treatments - treatment like skin peels and laser based skin lightening will help lighten the dark spots over the course of time