I have swollen lymph nodes where my shoulder joins my neck and one at the back of my neck. I have seen my gp who has told me to go back in sick weeks. The nodes are painful. I am on a biological treatment for rheumatoid arthritis. I have had an ulcer in my mouth which I've had since before Christmas. The dentist has looked at this and doesn't think it's anything to be concerned. Should I wait six weeks?