7 days back I started feeling pain in my throat, then after two days I found that i have ulcers on my throat area and at night time i got fever, and felt cold, then ulcers kept on increasing day by day, now the situation is that I am ulcers in my whole mouth, on my lips and one outside the below the lip area. Please suggest me what should I do or not, what may be the cause, is it a serious problem, because the pain is unbearable now.