I'm sorry to hear about the swelling on the left side of your face. It could be due to various reasons like an allergy, infection, or even a dental issue. It's usually a good idea to consult with a healthcare professional to identify the cause and get appropriate treatment. Do you remember any recent events, like a bite or dental work, that might have triggered this? How are you feeling otherwise? Let me know if there's anything specific you'd like help with.