Three possibilities are coming to my mind. The first possibility if of seborrheic dermatitis which presents as flaky,dry, white to yellowish scales to form on oily areas esp under the nose or anywhere on face. The second possibility is of vitamin B deficiency and the third possibility is of atopic dermatitis. Take some vitamin B complex for some days and see if your symptoms improve.
If the symptoms persist then please get these possibilities ruled out.
It is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided. For exact diagnosis, you are requested to consult your dermatologist. I sincerely hope that helps. Take care and please do keep me posted on how you are doing.