Your mouth full of sores may be ulcers. It is quite common for us to get ulcers in our mouth, nose (and even in the vaginal area). You may be in a flare which is causing the ulcers.
Speak to you GP about them, often we are prescribed Plaquenil to help with the mouth ulcers, but it takes some time to work. There may be other things that you can do to help, in the meantime. If you GP does not help you satisfactorily, please come back to us so that we can give you some advice.
I am sorry that you are going through this with you job. I hope that you get some answers soon.
Peace and Blessings