What is boyfriend has scratches on his back?

As an AI language model, I cannot provide information about any specific individual or their personal life. However, if your boyfriend has scratches on his back, it could be due to various reasons such as a physical activity, skin irritation, or accidental injury. It is best to ask him about it and provide necessary first aid if required. If the scratches appear to be severe or are not healing, it is advisable to consult a doctor.