Test a new product on a small area before broader use. This is an at-home use test, not the diagnostic patch testing performed by a dermatologist.
Follow a consistent method
The American Academy of Dermatology suggests a small area on the inner arm or elbow, using the normal amount twice daily for seven to ten days. Follow the product's application instructions; do not exceed a more restrictive label direction to perform a home test.
If a product is meant to be rinsed away, keep to its stated contact time. A successful small-area test does not guarantee that a product will agree with every area of your face.
Know when to stop
If a reaction appears, wash the product off and stop using it. Seek medical advice for a severe or persistent reaction. Do not repeatedly reapply to check whether the discomfort will go away.
Keep the rest familiar
Introduce one new formula at a time. Note its name and the date you started it. Those two details are more useful than trying to remember which of several new bottles came first.
If an Ozera product causes a reaction, you can also report it to us. Include the product name, order number if available, and what happened.
Further reading: American Academy of Dermatology: testing a new skincare product
Photography: COPAL / Unsplash. Editorial photograph.