According to WebMD, mild burning, stinging, redness and dryness are possible side effects of face bleach. While less likely to occur, severe side effects of face bleach can include blistering, cracking of the skin and blue-black darkening of the skin. If these more serious side effects occur, usage of face bleach should be stopped, and a doctor should be contacted immediately.
WebMD explains that hydroquinone, or skin bleach, should be tested on a small patch of unbroken skin for 24 hours before using. If the test patch becomes puffy, red, blistered or itchy during the test period, the product should not be used, and a doctor should be contacted. If the only reaction during the test period is mild redness, the product can be used to begin treatment.
Before using face bleach, the doctor or pharmacist prescribing hydroquinone should be informed of any allergies or pre-existing conditions. Allergies to hydroquinone's inactive ingredients (such as sulfites) can cause an allergic reaction or other problems. Asthma or other skin conditions such as psoriasis or eczema can also interfere with successful treatment. Very severe allergic reactions are rare. If symptoms of a serious allergic reaction appear, such as rash, itching or swelling in the face, tongue or throat, severe dizziness or trouble breathing, seek immediate medical attention.