For a few days mouth felt weird swollen and dry, then I got this sore on the roof of my mouth just thought it was a canker sore but if doesn't look like one. It is painful 24/7 I also have a headache, fever and diaherea. All my gums are swollen and sore what do I do? Do I need antibiotics. it definitely does not look like a canker and this constant pain on roof and gums has me worried