Getting rid of dark marks

Hey y'all Happy Wednesdayyy! Sorry for posting the dogs lmao, I'm j tryna figure out how to fade these dark marks.

I've tried brightening lotion and exfoliating but it doesn't seem to work. Idk how I got them to prevent them but maybe it's because I have to wear boots to work?.. I just wanna have pretty feet b4 summer so the dogs can be out/free Lol. Any advice is appreciated