It has been shown that ultraviolet light does have a bacterial static effect on the propionic bacteria that causes acne. Through ultraviolet exposure, you are slowing down the bacterial proliferation and inflammatory bacterial lesions.
However, you're still getting sunburned! This is simultaneously increasing your risk for skin cancer not only now, but when you become much older. Therefore, we need to find a better way to combat your acne rather than through ultraviolet light.