Tree Sap?

Would I be able to use tree sap in potions

Yes, you would lilyoak, provided that it is safe for you to eat.

Tree sap has also been used as a blood stopper for wounds, and it has antispeptic properties as well.

Don, not all tree sap is like that. It highly depends on the typeand species of the tree.

PINE sap, is highly antibacterial. It can also be turned into tinctures by adding corn alcohol. The needles can be simmered to make teas. Here is a link containing more knowledge than I have committed to memory.
Always avoid any white saps, and always try a tiny amount of any sap first before using it medicinally, if it has a tingling or numb sensation do not use it. Its up to the practitioner to know what species of tree they are working and what its properties are. Home work time.