I Am A Fair Skinned Woman.I Dont Go Out Too

I am a fair skinned woman.I dont go out too often in the sun also and also apply sunscreen while going out. But for the past one month i have observred my face and body is not fair anymore as it used to be. I am not a diabetic nor ahypertensive and i am not on any medication. What can i do to regain my lost colour? Pls advise. Thank you