It's a smart idea for all acne patients to strengthen your skin
against sunlight because while exposure can damage your skin in high amounts, you also need moderate exposure to generate vitamin D, nitric oxide, and mood - boosting endorphins.
However
sunlight isn't instantly bad
because it's needed to increase vitamin d levels and you can build your defences
against free radicals from
sunlight by eating more vitamin A, antioxidants, etc..