How Long Does It Take For The Exposed Skin To Heal?

I had a few spots on my face due to post inflammatory hyper pigmentation. Then, I tried using lemon as a natural remedy to fade the pih.finally, I ended up by removing a small layer of tissue too..now it's not so deep but it's visible..will the skin ever grow back to cover the small patch ? Or will it remain open forever ? How long does it take to heal or close up ? Thank u..