For the past month, I wake up in the morning with a swollen lower lip , and the tissue inside my lips is sore, like how they felt when I first got braces and the brackets had rubbed the skin away. I do have psoriasis , and I ve heard that auto-immune diseases can contribute to this. I m not on any medication or taking multi-vitamins. To the best of my knowledge, I have no food/environmental allergies. The only change I ve made is that I switched toothpastes. Any reason for this painful swelling?