After face slimming injections (botulinum toxin injections in the bite muscle) a relatively mild pain in the bite muscle may occur, which is a common adverse reaction and usually does not require treatment and will subside in a few days. However, if the pain is more severe, the chewing muscle may have been damaged during the operation, or the muscle membrane of the bite muscle or the lateral periosteum of the jaw bone may have been irritated. If it is accompanied by redness and swelling, there is a possibility of infection and immediate medical attention is recommended.