Here are few tried and tested methods on how to reduce the darkness around your mouth and nose.
How to use :
Apply a thin layer of tomato juice over the dark skin and leave it for 30 minutes. Wash it off with cold water. For best results repeat it everyday for a month.
Sandalwood and Turmeric Face Pack
I would recommend Sandalwood and Turmeric face pack only for oily skin. Always do a patch test before applying it on your face.
With the regular use of any of the above listed home remedies you can easily get rid of dark skin around your mouth and nose.