How long do you have to apply lemon juice your freckles for?

Applying lemon juice to your freckles is not an effective or recommended method for lightening or removing them. While some natural remedies suggest using lemon juice for skin lightening, there is no scientific evidence to support its effectiveness and it can even have adverse effects on skin health. Additionally, freckles are a natural part of many people's skin pigmentation and do not pose any health risks. It would be best to leave them as they are or consult a dermatologist if you have specific concerns about your skin.