Will an increase in carboxyhemoglobin cause oxygen content to increase?

No, an increase in carboxyhemoglobin will lead to a decrease in oxygen content. Carboxyhemoglobin is a hemoglobin molecule to which carbon monoxide is bound. Carbon monoxide has a much higher affinity for hemoglobin than oxygen, so when carbon monoxide is present, it will bind to hemoglobin in preference to oxygen. This reduces the amount of oxygen that can be carried by the blood, leading to a decrease in oxygen content.