My lower gums are swollen and underneath my tongue is swollen to. it hurts my teeth to eat. it started yesterday afternoon. what can it be?

Med Rxn vs infection: This is most concerning for a medication reaction. Many prescription medications can cause gum swelling. However, tongue swelling is even more concerning for a serious allergic reaction. If you are having any difficulty breathing or tongue swelling is worsening, you should go to the er immediately. On a less serious note, it could be an early infection causing the swelling. You should see a doctor.

Pain: It could be a dangerous abscess. Get to a doctor asap!

Lower gums: Looking at probably gum infection. Possibly tooth or salivary gland , or viral infection. When was last thorough dental cleaning?