Applying a hydrocolloid bandage immediately gives you a waterproof seal over the wound, so it basically lets you skip the “dry out and form a scab” part and go straight to the “sealed wound starts healing” part. The “wet” part is really just referring to how the wound is still “wet” underneath the scab.

I see hydrocolloid bandages in pharmacies/groceries a lot nowadays, so hopefully they’re helping modern swimmers avoid the pain you went through!