After feathering, an esthetician's hands should first come into contact with the client on _________.

The correct choice emphasizes the importance of proper technique and client comfort in the practice of esthetics. When performing a feathering technique during a facial, attending to the side of the face as the initial point of contact helps create a gentle and soothing experience. It allows for a soft transition onto the skin, minimizing any potential shock or discomfort that may arise from more abrupt contact elsewhere.

By beginning at the side of the face, the esthetician can gradually acclimate the client to the treatment, establishing trust and a sense of relaxation. This approach also allows the esthetician to better gauge the client's reactions and responsiveness to the treatment, ensuring a comfortable and effective experience overall.

The other options suggest starting at different areas that may be less conducive to a smooth or gentle introduction to the treatment process, potentially leading to a less favorable client experience. Focusing on the side of the face aligns with best practices in skin care and client interaction.