Hello, Welcome to Healthcare Magic. Cymbalta contain duloxetine salt and belong to SNRI class of medicines. It primarily used for anxiety and depression. It is also used for musculoskeletal pain, diabetic neuropathy and fibromyalgia. It is very rare to have this kind of side effect (huge pimple on the lips) with Cymbalta. But it can be rule out. Any drug can lead to allergic skin reaction, specially if started after the initiation of drug use. These kind of reaction also more common in person with auto immune disease. In my opinion, you should stop Cymbalta use and meet skin specialist for further intervention. You can also tell me about other associated symptoms to understand case and help you better. Wish you good health and all the best.