hello, my gums were sore yesterday morning and my mouth became in pain, i noticed a ulcer on the upper-inner part of my top lip on the thing- the thin layer of skin between my upper lips and gums. I went to the doctors and they said they didnt see anything it just looked a little red. Today, my mouth broke out into small white sores, and when i put my tongue between my upper or lower lip and my teeth , i have a strong taste, almost matallic. and my skin on the inside of my lips towards the bottom is red. What could this be, and thankyou