Before you use a new product
- Wash and dry a small area behind one ear.
- Dab a pea-sized amount and leave it for 24 hours without washing the spot.
- If there is redness, itching or swelling, rinse off and do not use the product.
- If the skin stays calm, start every other day and build up slowly.
Introduce one new active at a time. Ask your doctor before using retinol or strong acids if you are pregnant, nursing or managing a skin condition.