I've tried this, unfortunately to no avail.All I can think of to suggest is to use a good moisturizer on your face regularly.
I always make sure the strap isn't too tight, otherwise it triggers my gag reflex lol.I have never had this happen, but if it were me I'd try a few things:
1. Be sure strap is not too tight
2. Wash the strap with some soap and water to remove dirt and sweat
3. Try some powder on the strap or face
4. Wash face regularly and apply witch hazel
I know some of my helmets in the past had a terry cloth like covering over the nylon strap. I wonder if there is something aftermarket available to slip over the strap?
Good luck and enjoy your rides!
EDIT: Something like this is what I was trying to explain:
http://www.chinskin.com/
Unfortunately, it isn't possible to replace the straps on either of my helmets.I don't ride motorcycles, but from my experience in the military a long time ago may help. If you can change the strap, change it to a chin strap. There is less movement of the strap and it still holds the helmet securely.
Good helmets have removable liners or at least removable cheek pads. Get one and remove and wash them regularly. The straps don't come off so you have to wash that in place. Shampoo is great for cleaning, it's gentle and designed to clean off the oil your skin puts out. Keeping your helmet clean will help keep your skin clear. I've had these issues but usually only on multi-day trips.
Scott
This is great adviceMoleskin on the strap, or some other soft material to take away a bit of the scratchiness of the strap.