They say to have your white blood cells checked out if you get a sore throat etc when you are on carb. First time I had sore throat / swollen glands I had a test done at the doctor - tell them what you are taking and why you have to be tested you are given a same day blood test no matter how busy they are - my test was fine.
After that I used to get the odd swollen glands that used to come and go and I just waited to see what would happen which was always 'nothing'.
Read the leaflet that comes with your carb or google for the patient information leaflet - it is online. According to Dr Toft's little book on thyroid problems, problems with Carbimazole usually show up within the first few weeks. Whether that is tyre or not I don't know. Be safer to get checked out though, it is potentially very serious.
Should have said I never actually felt ill when my glands felt bad, nor did I have a sore mouth / mouth ulcers.
My pharmacist recommended taking vitamin C when I was taking carb, I take 2x slow release vitamin C capsules every morning, take CoQ10 too.
Hope you feel better soon.