Scabies...
I don't think you can actually catch scabies from a dirty bed, correct me if I'm wrong, but scabies is if you've been in skin to skin contact with an infected person with scabies for a long period of time i.e. anything over a couple of minutes? although you can catch crabs or aka pubic lice from sharing towels, bedding and/or mattresses with an 'infected person with pubic lice' but you can usually prevent this by having shaved pubic hair either both by you or the WG, hence why we rarely see full 70s brush on WGs anymore, few but rare.
and just to answer another question before it arises, no you can't catch crabs in your hair but it can;
You can get crabs whenever some part of your body that has coarse hair (such as the pubic area, eyelashes, eyebrows, facial hair, chest, or armpits) comes into contact with the infested pubic or other course hair. Crabs do not usually attach to head hair.
so feel free to lay your head down on that dirty bed
just make sure your beard is trimmed or shaved