Hello & welcome to Just Answer.
Probably what you have now, by having gone through your history, but without the benefit of a detailed clinical examination, is ‘Seborrheac Dermatitis’. The area of face that you mention, the involvement of back, the flare ups and remissions, are all pointing to this diagnosis.
Sorry, but you will be requiring a sort course of antibiotics now, so that a remission is achieved. This particular disease is marked by chronicity. You will also have to avoid hot food, spices, chocolates, etc. Best wishes.
It could be possible that it could be anything else such as: atopic dermatitis, eczema, asteotic eczema, cutaneous candidiasis, contact dermatitis, drug eruptions, Pemphigus, Pityriasis rosea, Roasacea, Tinea, lichen simplex, lupus, xerotic eczema, exfoliative erythroderma, chronic granulomatous disease, vitamin B and/or zinc deficiency, erythrasma, and there can be any more number of possibilities.
I had referred to it as chronic, because you said you have it for over a year now, and sometimes your face feel great (for 2/3 days). Moreover, with a previous history of acne, and with the specific area involved, with you mentioning that the area of involvement is very oily, and your back is covered with in spots, seborrheic dermatitis comes first to the mind. However, clinical correlation is required to reach some conclusion, following which some other confirmatory tests shall be required.
If one has been using a lot of antibiotics and over the counter products, the clinical picture would never remain as per the text books. Your dermatologist has to correlate your history with the examination findings. It would be in your interest to seek your doctor’s opinion before you use some over the counter product or antibiotics.