Final answer:
Sunscreen should be applied at the end of a facial treatment if the client will be exposed to sunlight, using a broad-spectrum SPF 30 or higher sunscreen. It should be reapplied every two hours, or after swimming or sweating. Those with unusual reactions to sun, like Kerry's rash, should seek medical advice.
Step-by-step explanation:
Sunscreen should be applied during a facial treatment at the end of the procedure, especially if the client will be exposed to sunlight immediately after. It is essential to select a broad-spectrum sunscreen with an SPF of 30 or higher, as recommended by the American Academy of Dermatology, to protect skin against both UVB and UVA radiation.
The active ingredients within sunscreens, such as derivatives of PABA like Padimate O, help achieve this protection by being less soluble in water and therefore more likely to stay on the skin during activities like swimming or sweating.
Melanin in our skin offers some natural protection against UV radiation by absorbing it and preventing deeper skin tissue from damage. However, exposure to excessive UV radiation can still be harmful, which is why the use of sunscreen is crucial. The application of sunscreen should be consistent; even water-resistant products should be reapplied every two hours, or after swimming or excessive sweating, as no sunscreen is completely waterproof.
For someone experiencing a rash as described by Kerry, it's important to note that not all rashes from sun exposure are sunburns. A medical professional should evaluate her condition to determine the cause and recommend an appropriate treatment.
It is also worthwhile to be aware of the skin's natural response to sun exposure, which includes the release of melanin, and the benefits of obtaining vitamin D through foods or supplements instead of excessive sun exposure.