I have a mouth ulcer size 2.5cm near my throat, since last 20 days, it has caused due to heavy stress and due to wrong medication during fever. I have been taking Renifol/B-Complex Multivitamin tablets, Rebagen, and Using Xylocaine Viscous before food. I would like to know does fever comes because of pain due to ulcers? How much time it take to cure completely?