A skin test/patch can be relevant before hair removal to:

A skin test or patch can be relevant before hair removal to check for sensitivity or allergy to the products used (such as certain waxes or pre/post products) and to gauge how the client's skin reacts, especially for clients with sensitive skin or relevant medications. Combined with intake questions about medications and conditions, this helps the cosmetologist avoid adverse reactions and decide whether the service is safe. Recognizing the role of testing and intake before hair removal is part of the safety content.