Upset about HYPOPIGMENTED upper lip scar b/c I AVOIDED sun. When is it time to expose it to UV rays? (photo)

Isn't there a time to start exposing the scar rather then avoiding it since UV rays are needed to repigment? I have a hypopigmented vertical line scar from a stitched up split upper lip twelve months ago. I feel like there's a time to avoid the sun AND a time to expose your scar when it comes to pigmentation, so I'd like some professional feedback as to how to go about getting UV rays to repigment this little vertical basterd. Thanks, Scott