My Skin Type Is Oily, I Ll Be Turning 21

My skin type is oily, i ll be turning 21 within 6 months, there are days when my skin is absolutely healthy (like it has natural glow and acne free,etc)but days when pimples occur and when they do THEY OCCUR THE EXACT SAME SPOT where the previous spot occured why does this happen?is this becos of low immunity? kindly let me know and thats why i do exercise (breathing & and other physical),cardio(i go for walk or sometimes i brisk walk),also when i eat junk pimples begun to reappear in the above mentioned format i wash my face with chickpea flour n turmeric , i tone my face with ice cube or cold or rose water and moisturize with Aloe vera gel by Patanjali,i exfoliate once a week ,i steam my face once a week,doing all these where am i going wrong,i also have few scars on right side of my face which have lessend but not going away,i want to have healthy, clean ,scar free n poreless skin using NATURAL substances