The gel causes a strong tingling and warmth — is that normal or should I wash it off immediately?

The river sponge particles in this gel are designed to create an intensive surface-level stimulation, so a distinct warming, tingling, or prickly feeling during the contact time is normal and expected. It usually subsides within a few minutes after rinsing. However, the sensation should not be painful, and the skin should not become intensely red, swollen, or develop a burning sensation that persists after rinsing. If the discomfort is sharp, if you see hives, or if redness lasts more than 30 minutes post-rinse, remove the gel immediately with plenty of water and discontinue use on that area. People with reactive or thin skin often feel the effect more strongly; for them, a 30–60 second contact time may be sufficient. Glycerin is included to help limit excessive dryness, but you may still notice temporary tightness — apply a fragrance-free moisturiser after rinsing. Do not reapply on the same day if the skin reacted strongly.