Yes, this device is made to be used on wet skin. You can moisten your skin with some water before use. You can decide for yourself whether you prefer to use the device on wet or dry skin, both types of usage make your skin feel firmer, but the tip glides over wet skin more easily for a more pleasant and gentle experience.
If your skin is dry before the end of the session, apply some more water to your skin to make the tip glide over the skin more easily again.
Please do not use the device under the shower.