First we need to access whether it is only tanning or facial pigmentation which can occur in specific areas . In any case you need to start using a sunscreen and a non steroid based lightening agents. Also treatment like Microdermabrsion and peels are available to improve skin tone and texture.
Pls visit a dermatologist near you or visit my website www.yslclinic.com for fixing appointment if you are in Delhi or ncr.
avoid excess sun exposure and pollution. start using suncros lotion 30 spf regularly 3 times daily. regards