I have rheumatoid arthritis and lupus, I m 37 years old. I m on prednisone, methotrexate, sulphasalazine and hydroxyquine. Since starting methotrexate 5 weeks ago I ve felt unwell. Fever, throwing up, headache, extremely painful mouth sores. Now I ve noticed a large lump under my armpit. Over a week it s just gotten worse. Should I be concerned?