There's not much you can do about mechanical injury, bar limiting the sex. I would make sure you lube well for the first couple of clients, to stave off it getting worse down the line. As said, also try Skyns to see if latex is exacerbating the issue. Also perhaps don't allow fingering unless they have trimmed nails.
I found one of the worst things is men who 'dagger', or do a diluted version at least, i.e. withdrawing completely with every or most thrusts - they often miss, and I found this quickly makes the entrance to the vagina sore.
Also, before bed, have a warm bath with some cheap cooking salt thrown in, and put some Sudocrem around the outside of your vagina, and try something like MultiGyn Actigel inside, or a vaginal moisturiser.