Complex sentence: The lack of oil causes excessive dryness of the skin, leading to redness and a burning feeling; redness and burning are also common symptoms of a sunburn, so the two conditions are often mistaken for each other.
Split into simpler sentences: The lack of oil causes excessive dryness of the skin, leading to redness and a burning feeling. Redness and burning are also common symptoms of a sunburn, so the two conditions are often mistaken for each other.