What should be the first action taken if a client experiences an allergic reaction?

In the event that a client experiences an allergic reaction, the immediate and appropriate action is to remove the product that has caused the reaction and provide medical assistance if necessary. This is crucial because removing the irritant can help prevent further exposure and potentially worsen the reaction.

Providing medical assistance is also vital, especially if the reaction is severe or if breathing difficulties arise. Quick action can be life-saving, as some allergic reactions may escalate rapidly and need professional intervention.

While applying a cold compress may help soothe mild irritation, it's not the primary step if an allergic reaction occurs. Continuing with the service is never advisable during an allergic reaction, as this could exacerbate the client’s condition. Offering the client water might help in some cases, but it does not address the root cause of the allergic reaction. Thus, prompt removal of the offending product and seeking medical help are the most effective measures in safeguarding the client’s health.