As I said above, why wet a wet wound? There is an answer and that is to help particulate matter loosen and come away from the skin leaving less staining. It works, but so do other methods. Hydrocolloid does not induce infection if left in situ for days, but you can bet that cultures from under the dressing will grow Staph aureus, Coliforms and Pseudomonas sp on and dressing left unchanged for several days. Is that bad - not usually, but it can be.
Here's a graze from 2014.
http://www.rotorburn.com/forums/attachment.php?attachmentid=307945&stc=1&d=1423640267
Deep - 5mm below the dermis and complicated by adjacent epidermal necrosis (like a deep burn but caused by blunt compression) and a gouge-like fracture in the ulna along the point of elbow. The small amount of forearm redness and swelling seen in this pic was massive the next day. Any deep and necrotic wound is an infection risk. Swelling increases the risk. Underlying fractures escalate the concern about infection. This was my elbow after a trail saboteur got me at speed on nasty, rocky terrain and it was managed very simply, without antibiotics or complex dressings.
After 30 odd years of medicine, including a decade of trauma-dominant work and after what has happened to me over the years, I'll say again that warm soapy water and palm of hand scrubbing for 10 minutes (makes you want some now), plus daily changes of Op-Site Flexifix UNTIL you can leave a dressing in place without drowning in it when it pops each afternoon is really the best way to go unless you have a desire to experiment with more expensive alternatives that are definitely no more comfortable.