No, the term "existing" does not necessarily imply being constantly present. "Existing" generally refers to the state of being or the fact of being real, actual, or in existence at a particular time or in a particular place. It means that something has objective or subjective existence, either in the physical world or in abstract or conceptual realms.
While some things may be constantly present and existing, such as the laws of nature or certain fundamental concepts, many things have a temporal or spatial aspect to their existence. They may come into existence at a certain point in time, cease to exist at another point, or exist only in certain locations or contexts.
For example, a physical object may exist in a particular location for a specific duration but may not be constantly present everywhere. Similarly, abstract concepts, ideas, or thoughts can exist in someone's mind for a period but may not persist indefinitely.
So, the state of existence can vary depending on the nature of the entity in question and the context in which it is considered.