Can I use it on sensitive skin, or if I have a cold sore or chapped lips?

The skin around the mouth is thinner and more reactive than most of the face, so a few situations call for caution or skipping the patch entirely:

• Cold sores, cracks or any infected or broken skin: do not apply the patch over these. Use it on intact skin only, and wait until the area has fully recovered before resuming.
• Chapped, peeling lips: if the chapping extends into the skin around the lip line where the patch sits, it is better to wait — occlusive contact on compromised skin can sting and cause redness.
• Very reactive or sensitivity-prone skin: introduce the product cautiously. A sensible approach is to test it on a small area first, keep the first wear brief, and see how the skin responds before using it as intended. If burning, itching or redness appears at any point, remove the patch and discontinue use.

Also keep the patch away from the eyes — it is designed for the perioral zone only. If you have a diagnosed skin condition around the mouth or are unsure whether an active peptide product suits you, check with a dermatologist before use.