Final answer:
The skin suction and cold spray machine should only be used on healthy and intact skin.
Step-by-step explanation:
The skin suction and cold spray machine should only be used in healthy and intact skin. Using the machine on damaged or broken skin can potentially worsen the condition and lead to infection. It is important to avoid using the machine on dry and flaky skin as it may cause further irritation and sensitivity. Similarly, using the machine on oily and greasy skin can make it difficult for the suction and spray to effectively work.