[skin concerns] developing discolouration underneath my nose. Please help!

I'm about 4 months post accutane but I starting developing this weird discolouration under my nose while I was on my treatment. I'm not sure what it is. I do wear 60 FPS sunscreen religiously but it seems to be getting worse. Makeup helps but I was thinking of looking into skin lighteners or something. What do you guys think? http://m.imgur.com/mtG3x6S