Seborrheic dermatitis or psosriasis or sebopsoriasis?

I lived in an room without cleaning it for 3 months and in the 3rd month i developed a scaly irriating spot behind my ear , first said dermatitis and then lesions were not curing , so i went to doctor \this it was sebopsoriasis i have lesions on hand , chest , back , scalp , legs including Groin area what is it? why did i get this(due to not cleaning room for 3 months or what)it all starts with small dots, later expanded my parents or my grandparents doesnt have any skin disease Please help

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