Inflammation of the tonsils is an immune response. That means you must eliminate what foods are upsetting your digest, correct digestive problems, supplement your diet and see if that quiets the immune system.
You also can use the herb Oregano (vulgarus) on the swollent part to help with the swelling in the short term.
You most likely have other health issues that are also related to digestion and poor nutrition. What other symptoms do you have?