Tinea Versicolor and Pytiriasis Alba

I have never had any problmes with my skin and recently I noticed white scaly dry patches on my face. It was only small and on my right cheek and than it started spreading on the other cheek as well. I also discovered discolored hypopigmented patches on my shoulders and they were scally, dry and itchy. I researched it and it looked like Tinea Versicolor. It was spreading really fast and it looks awfull. After I have tried using clotrimazole and terbinafine with very little or no effect, I bought selsun blue and left it on my skin over night.  It dried the patches and showed me new patches I didn't even know of by turning the skin extreemely dry and red. It also formed sth. like crust and the skin is very dry and wrinkly and feels very rough and thick. When I stretch my arms it hurts and is pulling and stretching the dried skin. Tinea needs sebum (skin oil) to spread and thrives on oily skin. I really need to put something neutral (vaseline) over the Tinea patches to fix the dryness from Selsun treatment, but was wondering if it will help Tinea to spread more? And how long will it take to completely kill this fungus and how will I know it? And patches on my face look like pytiriasis alba, but I've read it only happens to children? I am 27 years old. How can I treat it? Why is it happening?

I have lost 5 stone in 9 months thanks to low carb, daily exercise and no simple carbs like sugar, pasta, bread etc. in my diet. I am eating 1200-1500 calories per day and about 50g of carbs all coming from little fruits and mostly vegetables. I was wondering if I could be malnourished and it could be an underlying cause of my skin problems? What vitamins are depleted on low carbohydrate diet? I take A,D,C,B-complex,Folic Acid and E vitamin every day. No magnesium, iron or calcium, because they make me feel sick and drowsy. I also have allergy to dust mites and it got worse at the same time as fungus. What is the underlying cause of fungus?

Thank you for your answer.