I have had some cold sores appear right under my belly button, what can be the cause of this? they are various cold sores letting out liquid and blood

May be Herpes Simple: You should have it checked, it may be herpes simplex or it could be a bacterial skin infection or an allergic reaction to an insect bite. Meanwhile do not try to squeeze or puncture these cold sores as they may spread. The doctor might take a culture from the the liquid coming out of the sores and treat you with antibiotics if indicated.