Lemon juice is often promoted in homemade beauty routines because it contains citric acid and vitamin C. However, applying fresh lemon directly to the skin can cause irritation, dryness, or burning, especially for people with sensitive skin.
Using lemon on skin that is later exposed to sunlight can also trigger a stronger reaction and lead to redness, blistering, or dark discoloration. For that reason, mixing lemon juice with Vaseline does not automatically make it a safe or effective skin-brightening treatment.
For moisturizing, plain petroleum jelly is generally the safer option. Anyone wanting to treat dark spots or brighten uneven skin tone should consider products specifically formulated for the face rather than relying on acidic homemade mixtures.