Seems like you are pushing yourself too hard doing the same thing too often and without enough care for your body. You can always say no to certain activities or change them to other things, you won't lose tokens for it.
Members really want to see a model having fun with it more than anything else, so when it stops being fun, change to doing something else. Most members will enjoy the change and just go with it.
Every person only has a certain amount of physical or sexual energy. You must learn how much energy to expend per shift, and a few ways to extend that if required. Some things can be faked, some will be ways to protect that energy, and some will be to hold back some energy for those who deserve it.
Some of these things will be what you physically do, but some will be how you organize your room/shows, look for model advice on both.
I know quite a bit about friction or moisture based contact injuries externally if these are partly your concern? You can try a barrier cream, hot shower, and a good rest. There are some good ways to reduce future injuries too, wearing the right clothes, regular changes/ showers, and skin protection measures. Regular work also tends to build up a resistance to injury, but it does look like a bit of a tan in that area so you may not want that.
The most important thing is to keep working on doing other things, and to set boundaries for when the things you are doing go too far for you.