Exposure to the sun may prove good initially to get a tan and mask off acne, but it could lead to further breakouts of acne due to dried and irritated skin. It is to be realized that the excessive suns rays could cause premature aging and skin cancer, with a sunscreen of at least SPF (sun protection factor) 15 that is non-comedogenic or nonacnegenic. This will prevent clogging of pores.
A sun-burn on exposure to the sun can make acne worse. So sun exposure can prove only to be only of short-term benefit with more acne outbreaks in the time of come. However sunlight provides us with Vitamin D that is good, so optimum and limited exposure to sunlight could prove beneficial for most skin conditions including acne.