Thanks for the query. It depends on multiple factors and whether you stay mostly indoor or outdoor. Are you on any other treatment? SStart a broad range Sunscreens to filter the harmful UV rays.  People usually don't use sunscreens as they may be greasy or make your face appear white.There are different type of sunscreens available and there is one for everyone, so find the one that will help you. Kindly meet a dermatologist to get your skin condition diagnosed and he will also recommend a sunblock along with other necessary measures. You can message me personally for any particular brand recommendations.