Complex sentence: Light therapy appears to provide a short-term benefit, but data for long-term outcomes, and for outcomes in those with severe acne, are sparse; it may have a role for individuals whose acne has been resistant to topical medications.
Split into simpler sentences: Light therapy appears to provide a short-term benefit, but data for long-term outcomes, and for outcomes in those with severe acne, are sparse. However, light therapy may have a role for individuals whose acne has been resistant to topical medications.