Could cerebral edema go away on its own?

Yes: THe skull has no room for brain expansion so edema is a critical condition. There are several ways to reduce brain swelling and thus reduce pressure from the skull There may not be time to let swelling go down on own. Speak to the neurologist

Cerebral edema: The resolution of cerebral edema is based on what caused the edema in the first place. It if is due to an infection or tumor and they are treated then the edema usually resolves on it own. It really comes down to what caused the edema in the first place.