I guess I've been doing it wrong for years. I've always left the rash uncovered so it would scab over.
I crashed last Thursday and got rash on my hip, elbow and knee. I left the elbow and knee uncovered and they scabbed over in less than 12 hours.
By location, I had to cover the hip location as it would be underneath my underwear. I used the Tegaderm on that.
This is how it looked after I got home from the ride:
This is how it looks today after a shower:
I had to use three Tegaderm patches to cover the wound.
I'll get to see the time difference between the Tegaderm and the scabs.