Pale yellow skin tone on face and chest.

My skin on face and chest from last 6-8 yrs has been dull and dark or maybe pale. its looks 3-4 shades darker than my hands and legs which has original skin tone. i thought it was bcoz of sun exposure n swimming. It is uneven and hyperpigmented on forehead and chin. i got 3 glycolic and 2 yellow peels done on my face. Though Hyperpigmentatio has improved significantly but there is no change in that dull or pale face complexion. Doc even asked me to get my ferritin levels checked n it was too low around 7 something. doc gave me iron tablets for 3 months which are over now.My question is, is that dark or pale skin which appears to be 3-4 shades darker is bcoz of low haemoglobin(iron deficient anemia) or is there any other reason. If its bcoz of anemia then how much time would it take for my skin to get back to its original skin tone given i take a proper diet. i'm really concerned about my dark dull pale skin tone on face coz it looks too wired as my hands and legs are too bright.