Restylane Refyne Thai label

The maker says the gel is used to add volume to facial tissue, and lists these indications: correcting moderate wrinkles, and shaping the lips, the cheeks and the tear trough.

The doctor chooses the area, depth and technique for each person.

It must never be injected into a blood vessel. The maker says this can block the vessel and cut off or kill tissue, and rare serious events have been reported, such as blindness or abnormal vision, stroke or brain bleeding, and skin necrosis. If vision changes, stroke-like symptoms, blanching of the skin or unusual pain appear during or soon after injection, injection must stop at once and a doctor be seen.

The Instructions for Use list as contraindications: a history of streptococcal protein allergy, severe allergies such as anaphylaxis or multiple severe allergies, and allergy to lidocaine or amide-type local anaesthetics.

The maker says to postpone use when the injection area or nearby skin is inflamed, infected or has a tumour. People who bleed easily or take antiplatelet drugs, thrombolytics or anticoagulants may bruise or bleed more, and safety in pregnancy, breastfeeding and under 18 years has not been established.

The maker lists bruising, redness, itching, swelling, and pain or tenderness at the injection site, which usually settle within a few days to a week.

Until the first swelling and redness have settled, avoid intense sun, UV and extreme temperatures. Ask the injecting doctor before laser, chemical peels or other skin-stimulating procedures.