Hi.. Thanks for the query.. Well, it looks like you have got either an allergic reaction to any food that you have eaten or there is any common ingredient in your foods that is causing an allergic reaction, while other causes can be due to burning the inside of mouth with any hot foods or chemicals.. It causes inflammation of the mucous membranes inside the mouth that leads to swollen feeling also smooth and reddish shiny mucous membranes.. I would suggest you to consult an Oral Physician and get evaluated and get clinical examination done.. As of now you should take anti inflammatory painkiller like Ibuprofen. Do salt water rinses and take a soft bland diet.. Avoid hot and spicy foods as they can irritate the mucous membranes.. Drink plenty of cool water and suck ice pops.. You can also take benadryl if any allergy is suspected.. Hope this information helps.. Regards.